LOS ANGELES, CALIFORNIA: Chrishell Stause paid tribute to her late co-star Billy Miller who breathed his last at the age of 43 on Friday, September 15.

According to People, Miller, who was best known for his roles in soap operas 'The Young and the Restless' and 'General Hospital,' was “struggling with manic depression when he died.” However, no specific cause of death was cited.

Stause, 42, worked with Miller on 'All My Children' when the Daytime Emmy Award winner joined the soap as Richie Novak in 2007.

The 'Selling Sunset' star played Amanda Dillon from 2005 to 2011.

Chrishell Stause's emotional Instagram post

Stause paid an emotional tribute to her friend Sunday on Instagram on what would have been Miller's 44th birthday.

Alongside a picture of the late actor giving her a kiss on the cheek on a red carpet and a photo of him with the words, “Billy Miller 1979-2023,” written over the top, the actress shared that she was still “processing” the tragic news of his demise.

“Too many feelings, but you are gone too soon and I’m so happy I got to work with you all those years, but also call you a friend. I hope you are at peace now 💔🙏," Stause added.

The actor's 'The Young and the Restless' co-star Eileen Davidson also paid tribute on social media and shared a throwback of the pair at the 2014 Emmys where they both won awards.

“I'm so sad to hear of Billy Miller's passing,” the Real Housewives of Beverly Hills alum wrote in a post on X on Sunday.

“His infectious charm and warmth left lasting impressions on all of us who were lucky enough to have him in our lives. Im gonna miss that mischievous smile. Love you Billy.”

Billy Miller's illustrious career

Miller went on to act in 'The Young and the Restless' from 2008 to 2014 after starring in 'All My Children' from 2007 to 2008, where he earned three Daytime Emmy Awards for his portrayal of Billy Abbott.

He also won outstanding supporting actor in a drama series in 2010 and 2013, as well as outstanding lead actor in a drama series in 2014.

Miller also starred in ABC’s 'General Hospital,' joining the soap as Jake Doe in 2014. He later took over Steve Burton’s role of Jason Morgan from 2016 to 2017, before starring as Morgan’s twin, Drew Cain, for two seasons when Burton returned to the series.