Muhammad Ali: The Greatest was broadcast in place of The Musketeers in a change to BBC One schedules prompted by the death of the three-time world heavyweight champion.
Ali, who had battled Parkinson's disease for 32 years, died in Phoenix, Arizona, on Friday evening local time after being admitted to hospital with a respiratory condition earlier in the week.
his funeral will take place in his home town of Louisville, Kentucky on June 10, where flags have been flying at half-mast since his death was announced.
Stars from around the world have been queuing up to pay tribute to him and the BBC documentary, which included contributions from Sir Michael Parkinson, David Beckham, James Earl Jones and former US president Bill Clinton, was praised by viewers who expressed opinions on Twitter.
He was The Greatest
-- Hon Lee (@mashupweb) June 4, 2016
Incredible documentary on BBC about Ali. The all time great. pic.twitter.com/ki8liBLLr1
-- V (@v_afc) June 4, 2016
Ali obituary program on BBC is pretty good. Doubt we'll see a boxer like him even in my lifetime.
-- Daniel Griffin (@GriffinDaniel) June 4, 2016
This Ali on bbc is superb viewing
-- Sam Clinton (@Sam9Clinton) June 4, 2016
Ali was an absolute boss, great programme on BBC, huge respect.
-- Rhys Parslow (@RhysParslow) June 4, 2016
-- John Williams (@JohnWill79) June 4, 2016
This Ali program on BBC One is brilliant.
-- Harry Robinson (@HarryRobinson64) June 4, 2016
Never been a huge boxing fan but watching the tribute on BBC 1 tonight on Muhammad Ali has been fascanating,what a great man.#AliTheGreatest
-- Michael Labron (@mixy111178) June 4, 2016
Great documentary on Muhammed Ali right now on BBC One.
-- E.I. ZUMA (@spacyzuma) June 4, 2016
This show on Muhammad Ali on Bbc one is so insightful
-- Papi D (@ManLikeRicardo) June 4, 2016