Emmy Rossum Mourns the Death of Her Rescue Dog Cinnamon: 'He Was My Best Boy'

Emmy Rossum/Instagram Emmy Rossum and her dog Cinnamon

Emmy Rossum is in mourning over the death of her canine companion of over a decade, Cinnamon.

The Shameless star, 34, paid tribute to her beloved rescue dog on Thursday, sharing a slideshow of the pooch throughout the years on her Instagram.

"We lost our best friend of nearly 14 years today," Rossum began in the caption, writing that Cinnamon "was loved" by her family — including husband Sam Esmail, their dogs Sugar and Pepper, and their cat Fiona.

"He loved eating, sleeping, and traveling. He loved barking at children and eating discarded pizza crusts off the street," she wrote of her late furry friend. "He loved being carried and he loved being loved."

"I will always be his mother," Rossum added. "He was my best boy."

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Rossum's followers flooded the comments section with condolences, with the actress' former Shameless castmate Cameron Monaghan writing, "Sorry for your loss. Cinna-man was a good pup."

"Ahhhh, so sorry for Cinnamon's passing 😔," Hilary Swank commented.

"RIP ❤️ So sorry for your loss," model Emily DiDonato shared.

On Thursday, Rossum marked her "first morning walk" without Cinnamon on her Instagram Stories.

Emmy Rossum/Instagram Emmy Rossum's dog Cinnamon

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"Our first morning walk without you was really hard bud," she captioned a shot of the Yorkshire terrier. "I love you. I pray you are hoarding all the discarded street bread in heaven."

She also posted a photo of herself cuddling Sugar, a terrier-Havanese mix that she also rescued years ago, during her walk.

"Hold the ones we love close," Rossum wrote alongside the shot.

Emmy Rossum with her dog Pepper

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Rossum is a huge advocate of rescuing animals and has worked with the Best Friend Animal Society, a nationwide animal welfare organization.

In 2016, she told PEOPLE that her furry family "rescue me as much as I rescue them."

"I've always been a large proponent of the no-kill movement and Best Friends is the leader of that across the country," she said. "So, that's hugely important to me and I just really believe that animals — I don't have kids yet — add so much to my family and my life and sense of happiness and a sense of comfort."