After a day of mourning, some of the biggest names on TV are uniting to celebrate the life of The Young & the Restless star Kristoff St. John.

St. John, 52, who played Neil Winters on the long-running soap opera, was reportedly found dead at his home in San Fernando Valley, California on Sunday by a friend who visited to check on him.

Police and paramedics were called, but St. John was declared dead at the scene.

The Los Angeles Police Department confirmed they investigated a death on St. John's street on Sunday for a possible alcohol overdose.

Several of the actor's soap opera co-stars have shared tributes to St. John, remembering him as a kind soul, beloved friend, and a consummate professional on set.

Shemar Moore, the Criminal Minds star who played St. John's half-brother Malcolm on Y&R, called him "the closest thing to a brother and a brother's love and a brother's mentorship that I've ever known."

"He didn't have to embrace me the way he did. When I came in and was trying to find my way and he saw how scared I was, he saw how nervous I was," Moore told People.

St. John's co-star, Eileen Davidson, remembered him as "a loving kind generous sweet hilarious gifted human."

"He left an indelible mark on all who were blessed to know him. I am so grateful to have been able to work with him and laugh with him."

Melody Thomas Scott said she was "brokenhearted" in her own tribute. "We will desperately miss my dear friend, Kristoff," she wrote. "We all loved him so much."

Bryton James, who plays St. John's son on the series, had one of the most touching tributes of all.

"There are no words for my devastation," he said. "For the last 15 years, Kristoff St. John has been my other father, my friend and in the beginning, my reason for feeling as though I belonged in the Y&R family. He was an unbelievable example of strength, given what he endured over the course of his life."

"But most importantly, he taught us all every single day how to choose to have fun with life no matter what. I will miss him forever...  His daughters Lola and  Paris will always have me as family."

Several of St. John's co-stars have revealed that the actor was still in pain after losing his 24-year-old son, Julian, to suicide in 2014.

Eric Braeden, who plays Victor Newman on Y&R, told People that the actor had "succumbed" to his depression after losing Julian.

"He was deeply, deeply caring about his son and deeply wounded by his son's death," he said.

"How do you live with the death of your son or your child?" Newman added. "It's unimaginable, I don't even want to go there. As soon as you begin to empathize with that and begin to think about that, you understand his pain."

In St. John's last interaction with fans, he shared a tweet by another user on his social media feed: "Grieving the loss of a child is a process. It begins on the day your child passes, and ends the day the parent joins them."

St. John had also filed a wrongful death suit against a hospital that treated Julian for schizophrenia following his death.

St. John was also placed in a psychiatric hold in 2017 after threatening to commit suicide, but seemed to be recovering and had even promised fans he would never repeat his "dark behavior."

"I have made great strides in the last [three] weeks," he wrote on Facebook a year ago. "I am healthy and thriving. I have reclaimed my strength. I am moving forward. I have no other choice. Following God's plan."

St. John's fiance, model Kseniya Mikhaleva, expressed her surprise in a since-deleted Instagram post about losing St. John.

"How did it happen?" she wrote. "How ??? Why did you leave so early ???? and left me alone ..... I can't believe. You were everything to me .... you were a loving father, a loving man .....how."

Along with Mikhaleva, St. John is survived by his daughters Paris, Mia and Lola.

If you or someone you know is struggling with suicidal thoughts, you can receive free, confidential help 24 hours a day by calling the National Suicide Prevention Lifeline at 1-800-273-8255.

[H/T: ET, TMZ]

Rest in peace Kristoff.