Olivia Wilde's "heart feels broken" following the death of her beloved dog Paco over the weekend (10-11Mar18).

The former House actress took to Instagram on Sunday to tell fans that her rescue dog had passed away on Saturday, her 34th birthday.

"Lost my best friend last night. Paco was a kind, wise, gentle, loving soul. I could post a thousand photos of so many adventures," she wrote besides pictures of them snuggling up together. "These pics remind me of how peaceful he made me. My heart feels broken right now. All I can ask is that you consider adopting a pup, and loving them with all you’ve got. Here’s to all the incredible friends of Paco who’ve been so kind to him over the years. I am forever grateful."

In early February, she had shared a close-up snap of her white pooch and revealed she had been with the "handsome man" for almost 16 years and added, "What’s our secret? Same as most true lovers. Bacon."

In 2017, Olivia and fiance Jason Sudeikis adopted a pet brother for Paco - a three-year-old rescue they renamed Elvis. When introducing the new addition to her family, which also consists of son Otis, three, daughter Daisy, 17 months, she wrote: "This is our second adopted furry son and we cannot recommend it enough."

The Vinyl star had work commitments on her birthday, as she attended the South by Southwest (SXSW) festival in Texas on Saturday afternoon for the premiere of her new movie A Vigilante.

She later shared a picture of her and Jason snuggling up in bed with their kids.

"What could I possibly ask for on this 34th birthday? Just endless health and happiness for these magical maniacs. Thank you thank you thank you, a million times, thank you," she wrote.