Michael J. Fox has led Hollywood's tributes to the late Muhammad Ali.
The Back to the Future star has remembered the legendary professional boxer, who tragically passed away at the age of 74 from complications due to an ongoing battle with Parkinson's disease.
He wrote on Twitter: "Ali, the G-O-A-T. A giant, an inspiration, a man of peace, a warrior for the cure. Thank you (sic)"
Before adding in a statement: "Muhammad was a true legend - a champion in the boxing ring, and a champion for millions of Parkinson's families. We looked up to him as an example of grace and courage in the face of great challenges. He will be missed."
Meanwhile, singer and actress Jennifer Hudson also paid tribute to the late star.
Sharing a picture of the pair on Instagram, she wrote: "For some today will come around again and for somebody else now is the end ! Never rush the day away cuz u never know who's time your rushing away ! # #mohammadali (sic)"
Kate Hudson posted a video tribute to the sportsman on her social media account, which featured photographs of him overlaid by some of his most well known phrases.
She captioned it: "Yes you did Mr Ali. You shook up the world ... Sending love and light to the family #RIP #TheGreatest (sic)"
Muhammad - who was born Cassius Marcellus Clay Jr. - sadly passed away at a hospital in Phoenix, Arizona on Friday (03.06.16) after being taken ill the previous day.
The news was confirmed in a statement by family spokesman Bob Gunnell.
He said at the time: "After a 32-year battle with Parkinson's disease, Muhammad Ali has passed away at the age of 74. The three-time World Heavyweight Champion boxer died this evening."
Madonna also paid tribute to her "king", Muhammad Ali.
Sharing a photograph of them together, she wrote on Instagram: "This Man. This King. This Hero. This Human! Words cannot express. He shook up the World! God Bless Him ... What is going on??!! We are losing all of our National Treasures. Our Pillars of Humanity. He was the Greatest! (sic)"
Meanwhile, Paul Simon stopped half way through a performance of his Simon & Garfunkel track The Boxer to tell fans gathered at the Greek Theatre in Berkeley, California that Muhammad had passed.
He simply said: "I'm sorry to tell you this way, but Muhammad Ali has passed away," leaving a silence over the crowd as he played the last track of the night, The Sound of Silence.
And Puff Daddy had his own message for Muhammad, admitting he was "humbled" when the late sportsman came to see him on Broadway.
He wrote: "This pic means so much to me! The love he showed me he didn't have too. He always was excited to see me. He even came to see me on Broadway in A Raisin In The Sun. He sat thru a 3 hr play to see me. IT bugged me out. It humbled me. Thank you for the love. I MISS YOU. #RIPALI (sic)"
Whilst Justin Bieber added: "This is the ALI we should all remember! The fun loving man who was fully himself!! RIP CHAMP!!! (sic)"
Muhammad is survived by his wife Yolonda Williams and his nine children - Laila, Rasheda, Hana, Asaad, Maryum, Jamillah, Khaliah, Muhammad Jr. and Miya.
- Bang! Showbiz