Brian Dennehy, the Tony-winning actor who left an indelible mark in film, TV and theater, passed away on April 15, his family announced. He was 81. Mainstream movie fans knew Brian from his Golden Globe-winning role in "Death of a Salesman" and as Chris Farley's father in "Tommy Boy," but colleagues knew him as an "actor's actor" and a true professional. Click through to see how Hollywood is paying tribute to the six-time Emmy nominee…
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"Was lucky enough to see Brian Dennehy twice on stage, masterful in Love Letters, and monumentally heartbreaking in Death Of A Salesman. A colossus. What a loss." –Lin-Manuel Miranda
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"We've lost one of our great actors. Rest #BrianDennehy" –John Lithgow
"Condolences to the family of Brian Dennehy. A wonderfully talented actor." –William Shatner
"Just devastated to learn that the magnificent Brian Dennehy has died. They is no one i enjoyed working with more." –Mia Farrow
"RIP Brian Dennehy. Brilliant and versatile, a powerhouse actor and a very nice man as well." –Michael McKean
"He was truly a tremendous actor and his passing is such a terrible loss. Sending condolences to his daughter Elizabeth and the entire family. RIP #BrianDennehy" –Marlee Matlin
"Another day. Another piece of devastating news. For those who never got to see Brian's towering performance in 'Death of A Salesman,' it will go down as one of the crowing performances ever delivered in a stage. #RIPbriandennehy" —Josh Gad
"I met Brian in a bar, acted in a movie with him but the stage was what he loved. In rehearsal he said, 'This is it, kid.' He was a fellow nutmegger, mick and a Marine. They don't make his kind anymore." –Dana Delany
"We were shooting 3 Days With Dad & I'm basically carrying terminally ill dad Brian Dennehy from his hospital bed to the bathroom over & over. He's not a frail old man. He's a bull. 10th take I ask Brian for some help. Fake it a bit. Bad idea. 11th take was unpleasant. RIP" –Tom Arnold
"Very sad to hear about the passing of Brian Dennehy. He was a fantastic actor on the big and small screens, as well as theatre. Another great loss!!! RIP MM" –Malcolm McDowell
"Gutted. RIP Bear" –Titus Welliver
"I was deeply saddened today to learn that my costar in 10, Brian Dennehy, made his transition. He was one of the sweetest, kindest, most generous actors I ever worked with. His energy and love will be greatly missed on this planet." –Dee Wallace
"Sending sympathy to Elizabeth Dennehy and her family on the loss of her father, the great Brian Dennehy." –Brent Spiner
"I'm just devastated to hear we lost my beloved friend and colleague, #BrianDennehy. We were partners on two of my favorite films, Split Image and Best Seller. I've never laughed so hard as we did every day on the set or off. For a big 'tough guy,' he was a sweetheart. #RIPBrian" –James Woods