Courtesy of Brandi Glanville
Glanville shares Mason with ex-husband Eddie Cibrian, who is now married to LeAnn Rimes. The three stars got together at STK Steakhouse in Los Angeles to mark Mason's birthday, per the Real Housewives of Beverly Hills star's Instagram page.
"Happy Birthday Mason Glanville😀 💗" Glanville, 48, captioned a photo of the family on Wednesday. "It's my birthday too I spit you out of my womb 18 years ago today💗💗 this is literally the busiest month of my life💗💗💗"
Earlier in the day Glanville posted another picture of her with Mason, writing alongside the snap, "Happy Birthday Mason! You may legally be an adult now but you'll always be my baby boy💗💗I love you so much."
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Both Cibrian, 47, and Rimes, 38, also celebrated Mason on their respective social media pages.
"I can remember like it was yesterday holding this sweet human in my hands... a baby," Cibrian wrote on Instagram. "Now 18. A man. And just as sweet. And caring, and kind, and intelligent...a beautiful future ahead. Happy Birthday, young man @masoncibrian 💛 🥳🎉🎂#birthdayboy #18 #notsolittleanymore 😩"
"I cannot believe we have an 18 year old in the house.... WHAT?!" Rimes added in her own post. "Happy 18th birthday, Mason!! It has been a joy to see you evolve into the young man you are today. You are ridiculously handsome and as witty as they come, but most of all, it's your massive heart that inspires me the most. It's an honor and a blessing to be your stepmom. Here's to the rest of your life! I LovE you!"
In addition to Mason, Glanville shares son Jake, 14, with Cibrian. Although the former couple went through a rough patch after Cibrian had an affair with Rimes over a decade ago, the exes have put their past behind them and are working toward a cordial relationship.
The "Blue" singer said that "you have to consider everyone's feelings and you have to allow people to have them and you can't take them personally," admitting it's much "easier said than done, but at least we shoot for that."
Despite challenges, the artist said her family is "good" and isn't "what you would normally think" a blended family would look like. "Nobody's fighting, nobody's doing anything weird… it's interesting, the kids are older now, it's fun," she said. "The kids are happy and that's all that matters."