Sam Rockwell dedicated his Best Supporting Actor Oscar to the late Philip Seymour Hoffman.

The 49-year-old actor paid tribute to the late star, who died from an overdose in February 2014, as he picked up the accolade for his role in 'Three Billboards Outside Ebbing, Missouri' on Sunday (04.03.18).

He said: ''This is for my old buddy, Phil Hoffman.''

And speaking backstage at the Dolby Theatre in Los Angeles, Sam hailed his ''old friend'' as a huge ''inspiration'' to himself and his peers.

He said: ''He was an old friend of mine. He directed me in a play for public theatre. He was very close to me and an inspiration to all of my peers. People like Jeffrey Wright, Billy Crudup, Liev Schreiber, Mark Ruffalo, Josh Brolin -- whoever was in my age range, Phil Hoffman was the guy.

''He was a great director, he believed in theatre. He vowed to do a play a year, which I'm not sure he got to do, he was very busy doing movies.

''But he was a great inspiration and a great theatre director. He was also a bit of a jock, he was a wrestler, he played basketball. He inspired me and I could go on for an hour about Phil Hoffman. He was a good friend and a huge, huge inspiration on me.''

While up on stage, Sam credited his father for his love of movies.

He said: ''I'd like to thank the Academy, I never thought I'd get to say those words.

''When I was eight years old I was called into the principal's office and my dad was there looking very solemn and said, 'We gotta go, it's grandma.' When we got in the car I asked what was wrong with grandma and he said, 'Nothing, we're going to the movies.' ''

Meanwhile, Allison Janney picked up the Best Supporting Actress award for her role in 'I, Tonya' and began her speech with a joke.

She quipped: ''I did it all by myself.''

But she went on to pay tribute to her ''extraordinary'' fellow nominees, Lesley Manville, Laurie Metcalf, Mary J. Blige, and Octavia Spencer.

She said: ''My fellow nominees, you represent everything that is good and right and human about this profession. You are all extraordinary.''

And the 58-year-old star thanked screenwriter Steven Rogers for her ''gift'' of a role as LaVona, Tonya Harding's mother.

She said: ''Look what you did. You're a brilliant writer. Thank you for the gift of LaVona. I did not see this coming, you did.''

As well as the Oscar, both Allison and Sam have won Golden Globes, BAFTAs, Critics' Choice awards and Screen Actors Guild awards this year.