Colin and Livia Firth announced their split in December after 22 years of marriage
Colin Firth and Livia Giuggioli
Colin (L) and Livia Firth
| Credit: Jacopo Raule/Getty

Livia Firth has a sweet message for her estranged husband, Colin Firth.

The 51-year-old film producer shared a tribute in celebration of the actor's birthday on Thursday, writing on her Instagram alongside a shot of the actor wearing Elton John's costume from 2017's Kingsman: The Golden Circle, "60th and not feeling it 😍."

"happy birthday to the best partner in crime ever (for the last 25 years and counting) 🦋🌈," she continued. "(this is when Colin stole Elton John costume on the Kingsmen set ... 😂) #thursday #thursdayvibes."

Colin and Livia announced their plans to separate in December after 22 years of marriage. The former couple share sons Luca, 19, and Matteo, 17.

“They maintain a close friendship and remain united in their love for their children,” a rep said at the time.

The announcement came almost two years after the pair revealed that Livia had a relationship with another man, Italian journalist Marco Brancaccia, while they were briefly separated.

Livia (L) and Colin Firth
| Credit: Dave Benett/WireImage

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Livia accused Brancaccia of stalking her after their 11-month relationship ended in 2016 and, together with Firth, sued him in an Italian court for carrying out a “campaign of harassment.” (Brancaccia denied the accusations, and the case was settled out of court in July 2018.)

The amicable exes appeared to have remained close despite announcing their split last year, with Colin and Livia ringing in 2020 together in a New Year’s Eve photo shared on Instagram.

“How we ended and how we began ❤️ @massimoserini.official @karenalder @sarahdeweymassage Colin and many more ❤️ bye 2019 and helooooooo new decade! ???,” Livia captioned a slideshow featuring a smiling selfie of Colin in one photo and the group relaxing outside in lawn chairs in the other.

In January, the former couple came together to host a screening of Netflix’s The Great Hack, posing in a photo together alongside journalist/star Carole Cadwalladr and others for the event.

“#aboutlastnight hosting a screening @thegreathack @netflix with Colin with journalist extraordinaire @carole_cadwalladr and Chris Steele followed by a fascinating Q&A on the MOST important issue of our time — data,” Livia captioned the group shot.

A representative for Colin did not immediately respond to PEOPLE's request for comment.