Actor Shemar Moore, who had a long working relationship and close friendship with Kristoff St. John, posted a moving tribute to his “brother” after he learned about the Young & the Restless star’s sudden death at age 52 on Sunday.

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Moore opened up to PEOPLE.com about how St. John embraced him early on in his career.

“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 says about St. John who played Neil Winters on the soap opera. Moore played his younger brother Malcolm.

“He saw my six pack and all that, but he just saw me and he embraced me like a brother. If he hadn’t embraced me, I would have never got my sure footing in the beginning days,” he said.

Moore, 48, left the series to star in Criminal Minds and S.W.A.T., but says it was St. John who helped him lay the groundwork for a successful television career.

“Without Kristoff St. John, there’s no Neil Winters. Without Neil Winters, there’s no opportunity for Malcolm Winters. And without Malcolm Winters, there’s no Shemar Moore. And if Shemar Moore didn’t get my chance to try on The Young & the Restless, then I don’t sit here today with let alone this career or this life. Not in this way.

“And I will give Kristoff, and I always have given Kristoff — and I’m not just saying this to be cute because of what’s happening today — I told him in the beginning because he embraced me the way he embraced me is the only reason that I have the life and career that I have,” explains Moore.

“I would have life, but it would have been on a very different tangent and a very different lane. I will always give Kristoff that credit. I will always thank The Young & the Restless for taking a chance on me so that I can have this career. Kristoff was there in the trenches with me. Victoria Rowell, Tonya Lee Williams,” he says mentioning his other former castmates, “but Kristoff, day to day to day, he rooted for me. He didn’t have to. He didn’t have to, and many wouldn’t, but he rooted for me; he helped me; he held my hand; he said, ‘Stick with me, bruh, I’m going to show you the way and then you do what you’re doing.’ “

Says Moore, “He was the sexiest black man on television from what my aunties and grandmothers told me before I’d ever knew that I was ever going to share the stage with him on The Young & the Restless.”

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“He opened doors for me and many. He opened doors for people who don’t even realize he opened doors, but he did,” he says. “He opened doors and he was so committed to his craft. He always wanted to be better. He wanted to touch people and he did.”

Leading the way for Black men on daytime TV

St. John played Neil Winters on ‘Y&R’ since 1991. He earned him 9 Daytime Emmy Award nominations and 10 NAACP Image Awards. St John’s acting credits also included portraying a young Alex Haley in the ABC miniseries, Roots: The Next Generation, as well as a memorable appearance on The Cosby Show playing an eccentric teenager who dated Denise Huxtable (Lisa Bonet).

According to his show’s cast bio, Kristoff St. John made his television debut at age 7 in the ABC series, “That’s My Mama.”

He went on to star in the series “Charlie & Company” with Flip Wilson, Gladys Knight and Della Reese, and later had roles in “The Bad News Bears” and “The San Pedro Beach Bums.”

St. John also had a recurring role on “Hangin’ with Mr. Cooper” and made appearances on other TV shows, including “Diagnosis Murder,” “Arli$$,” “The Jamie Foxx Show,” “Martin,” and “Living Single.”

In December 2014, the daytime soap star shared some heartbreaking news about a personal tragedy revealing that his son Julian had committed suicide on November 23. The actor and his ex-wife, Mia, described their son as the “light” of their lives.

“He’s clearly been through a s— ton of adversity. He lost his son — you don’t wish that on your worst enemy. He had his issues, but he was strong, he persevered,” Moore says.

“I think yesterday, he was tired — he was just really tired and I’m sorry I couldn’t have been there more,” he says, in reference to St. John’s death.

“It’s not my fault, it’s not anybody’s fault. But as sad as it is, and it’s f—— sad, like I said, it hasn’t sat with me. But his heart was undeniable. He’s a goofy motherf—–, he’s a silly goofy motherf—–. He’s so goofy. … He’s a silly dude, but he’s so talented.”

“This is not how he’s going to be remembered in his last days. He’s going to be remembered for his journey, for how much he loved his children — Paris, Lola, and Julian, his son who had a hard time and took his life. And Kristoff, he weathered that storm and he loved me and he loved Allana and his current fiancée, I don’t know her name — I never met her — but I was just excited him to see him in love again, just in love, somebody to share his heart with,” says Moore.

On Instagram, Moore continued his tribute saying: “Mr KRISTOFF ST JOHN….. There is no ME without YOU!!!!! You are MY BROTHER!!! I LOVE YOU!!! Sleep my dude…. REST IN PEACE… I’ll finish what YOU started!!! THANK YOU for YOUR HEART and TALENT!!!!!”

He told the website he will continue to make his friend proud through his work.

“With everything I’ve done, I’ve just wanted to make him proud and he’s always let me know how proud of me he is. I’m just so proud to have come into his life, worked with him on stage. This sucks, this f—— sucks,” he tearfully says. “I love him. I miss him, but I will always celebrate him and everything I do will be with the intent to make him proud.”

Law enforcement sources told TMZ one of Kristoff’s friends went to check on him at the actor’s home in San Fernando Valley Sunday, and found his body. Police and paramedics were alerted and responded to the house. Kristoff was reportedly pronounced dead at the scene.