Leonardo DiCaprioAlan Thicke, who played Jason Seaver on the hit ABC sitcom Growing Pains, passed away at the age of 69 on Tuesday after suffering a heart attack while playing hockey with his son.

The actor, who recently appeared on NBC's This Is Us and the second season of Netflix's Fuller House, was beloved by the industry as indicated by celebrities' reactions on social media. His family, friends and celebrity friends took to social media to express their condolences and sadness over losing the TV icon.

Alan Thicke: His best TV work

See some of their posts below.

His ex-daughter-in-law, Paula Patton

Bob Saget

Dane Cook

Orlando Jones

Alyssa Milano

Howie Mandel

William Shatner

Ellen DeGeneres

Lori Loughlin

Will Friedle

Brett Dier

Ed Helms

Leonardo DiCaprio