Leona Lewis Says She Was 'Deeply Hurt' by Michael Costello After He Accuses Chrissy Teigen of Bullying

Leona Lewis is calling out Michael Costello one day after the fashion designer accused Chrissy Teigen of bullying him.

In a lengthy Instagram Story post, the "Bleeding Love" singer claimed that Costello, 38, made her feel "very awkward and uncomfortable" at a 2014 fitting for a charity fashion show that she claims she ended up not being able to participate in.

Lewis, 36, explained that she was speaking out about Costello — who claimed on Monday that he has "unhealed trauma" due to his alleged experiences with Teigen — because "the pot calling the kettle black in this situation doesn't sit right with" her.

"I usually don't speak on subjects like this," Lewis began her statement Tuesday. "But honestly I feel that I have to say something as I've dealt with years of insecurity from it."

"I don't condone any kind of bully behavior and I'm sorry for what Michael Costello went through," she continued, adding that she "wanted to share my experience in 2014."

"I was asked to take part in a fashion show to raise money for charity. Michael Costello was assigned as my designer. As an excited young woman, I flew all the way to New York and was so honored to work with him because I adored his dresses."

getty (2) Leona Lewis, Michael Costello

Lewis said that she was made to feel "very awkward and uncomfortable" at her fitting because the dress was a sample size, and alleged that Costello and his team "clearly did not want to alter it to fit me."

"This came as a total surprise because weeks prior I was told that they would make the dress work for me," she wrote. "At the next fitting, the night before the show, with no explanation at all, Michael refused to turn up. He no longer wanted to dress me and he abandoned his commitments to me and the show which made me well aware that I wasn't the body type required."

Leona Lewis/instagram Leona Lewis' Instagram

Leona Lewis/instagram Leona Lewis' Instagram

Leona Lewis/instagram Leona Lewis' Instagram

RELATED: Chrissy Teigen Speaks Out After Past Online Bullying: 'I Was a Troll, Full Stop - I Am So Sorry'

The singer said that she was "so embarrassed and deeply hurt" by Costello.

"Because I didn't look like a model size, I was not permitted to walk in his dress. I had to sit in the audience and was asked by press why I didn't walk in the show," she continued, adding that she had to "come up with excuses as I was so humiliated by it all."

"I feel like I was made to look as though I pulled out and was being difficult and as an affect [sic] of those actions I suffered a lot, both personally and professionally," she continued. "The most hurtful thing is that it was to raise money for charity, and this went against everything we were trying to do."

Leona Lewis/instagram Leona Lewis' Instagram

Leona Lewis/instagram Leona Lewis' Instagram

Leona Lewis/instagram Leona Lewis' Instagram

Lewis said that she was "left with deep insecurities" after the experience and has "had to work hard over the years to love my body."

"I'm so proud of how curves are celebrated today but back then it was a different story and there was hardly any representation for women who were not a standard small size," she continued. "I know that his designs are catered to women of all sizes now, and I'm glad he saw the light over the years. We all make mistakes, I know I have, but at this time I feel that when people apologize (Chrissy) and show sincere remorse and rehabilitation for their actions, we should embrace them and not try and kick them when they're down."

"I'm not discounting Michaels experience as that is an awful thing to go through and I wish him so much love and healing," she said. "I'm sure this will come as a shock as I never told him how this made me feel. But the pot calling the kettle black in this situation doesn't sit right with me. Bullying comes in many different forms. We need love, we need accountability, we need forgiveness, none of us are perfect."

Lewis concluded, "We are trying our best and learning. I'm sorry for anyone who has gone through any kind of bullying, I'm also sorry if I've ever hurt anyone without knowing it as I'm sure was the case with Michael."

Never miss a story — sign up forPEOPLE's free weekly newsletter to get the biggest news of the week delivered to your inbox every Friday.

Costello responded on his own Instagram Story Tuesday, sharing a photo of Lewis wearing a red dress seemingly designed by him.

"@LeonaLewis No dis no shade no hate, I love you and your music I still follow you but not sure what [happened]," he wrote. "I've reached out to you personally and I have 7 emails from the last 4 years and these past 9 weeks from your team and stylist still requesting looks last email 05/17/21."

"Leona I am still a fan and I am not coming for you. But let's talk about what you were feeling about this dress I thought you were happy," he continued.

Michael Costello/instagram Michael Costello's Instagram

Michael Costello/instagram Michael Costello's Instagram

Michael Costello/instagram Michael Costello's Instagram

In another slide, he shared a photo of himself with the singer, saying that he was not sure what happened "between the middle men or what happen in translation."

"Love you Leona," he wrote, sharing in another slide a screen grab of an alleged email from Lewis' team.

In a statement shared with PEOPLE on Wednesday, the designer said he had been preparing for his fashion week show in 2014 when he received a request from Lewis' team to dress her for the event.

"Coincidentally, I had prepared to show a new collection of red silhouettes so I thought it would be ideal to lend her one of my never-before-seen showpieces for her charity event, then have it returned just in time for my show," he said in the statement. "Unfortunately, none of the red options worked out for Leona. There was no way for me to make her an alternative option as I was, and still am, based in Los Angeles. If we had known about the event more than 7 days in advance, which is the timeframe we had, we could have made something custom for Leona without a doubt. Please keep in mind that my team and I were already in NYC at the time finalizing last minute details for my fashion show."

"I was blindsided by Leona's comments because the story she shared on Instagram paints a very different picture than the one she led me to believe for years. If she felt this way, I wish she could've said something to me about this privately, especially when I just spoke my truth in regards to Chrissy Teigen and others trying to blacklist me," he continued, adding that he has reached out to Lewis privately. "I have always offered to make something custom and special just for Leona. I am always here for her."

On Monday, Costello shared a lengthy statement and unverified screenshots of a 2014 conversation with Teigen, 35, on Instagram — the same day that the cookbook author shared an apology for her past bullying of Courtney Stodden and other celebrities.

"For the past 7 years, I've lived with a deep, unhealed trauma," Costello wrote. "I didn't share this with anyone because I was living in fear. In fear of losing some of my most profitable brand relationships; in fear of losing friends and allies; and in fear of being blocklisted [sic] even more by the power elites who run the industry."

Costello went on to claim that Teigen affected his career after she commented publicly on his Instagram after he was accused of racism in 2014. (Costello has claimed that a comment circulating in 2014 in which he appeared to use the n-word was photoshopped by a former, disgruntled employee.)

"She apparently formed her own opinion of me based on a photoshopped comment floating around the internet which has now been proven to be false by Instagram and since taken down," he said.

Costello claims that he reached out to Teigen to explain what had happened, but that she told him his "career was over" and that "doors will be shut" moving forward.

He also claims Teigen and her longtime stylist Monica Rose — who has said she began working with the Cravings entrepreneur in 2016 — went "out of their way to threaten people and brands that if they were in any shape or form associated with me, they would not work with any of them."

Reps for Teigen and Rose did not immediately respond to PEOPLE's request for comment Monday.

In a Medium post Monday, Teigen apologized for her past hurtful tweets, writing that "not a day, not a single moment has passed where I haven't felt the crushing weight of regret for the things I've said in the past."

"There is simply no excuse for my past horrible tweets. My targets didn't deserve them. No one does," she wrote. "Many of them needed empathy, kindness, understanding and support, not my meanness masquerading as a kind of casual, edgy humor. I was a troll, full stop. And I am so sorry."

RELATED: Chrissy Teigen Steps Away from Never Have I Ever Voiceover Role amid Bullying Controversy

"There's no justification for my behavior. I'm not a victim here. The subjects of your sympathy - and mine - should be those I put down," Teigen wrote. "The truth is, I'm no longer the person who wrote those horrible things. I grew up, got therapy, got married, had kids, got more therapy, experienced loss and pain, got more therapy and experienced more life. AND GOT MORE THERAPY."

"Life has made me more empathetic. I'm more understanding of what motivates trolling - the instant gratification that you get from lashing out and clapping back, throwing rocks at someone you think is invincible because they're famous," she continued. "Also, I know now how it feels to be on the receiving end of incredible vitriol. Believe me, the irony of this is not lost on me."

Teigen later concluded the post by writing, "We are all more than our worst moments."