'For the greatest man I have ever known': Life long friend Billy Crystal set to eulogize Muhammad Ali at public funeral in Kentucky

Billy Crystal is ready to go one final round with friend and foil Muhammad Ali, as he is set to be one of the speakers to deliver a eulogy at the boxer's funeral on Friday.

No comic on stage could float like a butterfly and sound like Ali quite like Crystal.

Often imitated? That was Ali. His boisterous voice roared for decades, he would boast he was The Greatest, before it turned soft, raspy and silent as he battled Parkinson's.

Ali in his heyday was ripe for impression — and comics and sketch comedy shows all took aim at the champ.

Longtime friends: Billy Crystal is set to deliver a eulogy for boxer Muhammad Ali at his public funeral on Friday. The pair have been longtime friends as they met in the 1970s before Crystal's movie stardom. Above they are pictured in 2007

Crystal was still a relative unknown in the early 1970s when he was picked as part of a dais that would help roast Ali at a banquet. His routine became an act part of the rest of his career. Above they are pictured together

Long before movie stardom, Crystal was still a relative unknown in the early 1970s when he was picked as part of a dais that would help roast Ali at a banquet. 

Crystal's Ali routine — he also mimicked longtime Ali foil Howard Cosell — would become a part of his act for the rest of his career.

The comedian wrote about how the famed boxer gave him his seal of approval for the iconic impression in a 2010 essay for USA Today.  

'He loved it and started calling me 'little brother,' the nickname he still uses for me to this day,' Crystal wrote in the essay.  

He also wrote of a time when Ali asked him to run on a golf course with him, as he enjoyed the privacy it offered.

However, Crystal told him that Jews were not allowed there and that he couldn't go.   

Crystal remembered Ali last week on Twitter with a video of his 1979 performance called '15 Rounds,' with the caption, 'For the greatest man I have ever known'. Above they are pictured together

'He got angry. 'They don’t allow Jews? I’m a Muslim and they allow me! I will never run there again, little brother, I promise you.' And he didn’t,' Crystal wrote. 'That was the Ali I will never forget.'

Crystal is among the mourners scheduled to speak Friday at Ali's funeral. President Bill Clinton will deliver a eulogy.

It's easy to imagine Crystal will break out bits of his old routine and make an arena full of fans, friends and family feel for a moment that Ali is talking to them one more time. 

Ali's voice had been diminished for so long, that it was often modern-day artists who would introduce a new generation of fans to the boxer's quotes and quips through comedy.

Crystal remembered Ali last week on Twitter with a video of his 1979 performance called '15 Rounds,' with the caption, 'For the greatest man I have ever known.'

The '15 Rounds' performance highlights the legendary boxer's career and also includes impersonations of both Ali and famed sportscaster Howard Cosell.

Crystal's nearly 12-minute performance at Ali's 1979 retirement tribute show at the Great Western Forum captures both at their best: Crystal breaks out his impeccable Ali ('I'm so fast, I can play ping-pong by myself'); The Greatest can't stop laughing and later rises for a standing ovation.

The '15 Rounds' performance highlights the legendary boxer's career and also includes impersonations of both Ali and famed sportscaster Howard Cosell. Above they are pictured in 2011

Here are some of the memorable impressions of the wannabe Greatests:

CRYSTAL:

Ali was ready to spar another round, this time in a verbal war of words at breakfast with roommate Katharine Hepburn.

'If you put another biscuit in my face, I'm going to knock you upside your head ! I am still the greatest of all time!'

Crystal also roasted Ali during a guest spot for the fighter's 50th birthday celebration TV special

Ok, this wasn't the real-deal Ali but rather Crystal as he performed another spot-on impersonation of the former heavyweight champ (opposite Martin Short as Hepburn) in a 1980s 'Saturday Night Live' skit.

Ali was occasional guest — when he wasn't the subject of a roast — at Crystal's touring shows.

'He's been a truly great friend to me and a great friend to the world,' Crystal said when he introduced Ali before a performance.

Ali was a great sport when it came to his public persona, as well. 

The boxer took the pokes and jabs with more ease than when he was in the ring from comedians like Crystal and various other TV shows and personalities who found Ali's larger than life aura easy to duplicate on stage or screen.

Crystal and Ali forged a friendship that spanned 40 years. 

But in the battle of the one-liners over the course of their friendship, Crystal was the undisputed champ of comic relief.

'I'm announcing tonight that I'm changing my name again because I've got new religious beliefs,' Crystal said, as Ali, on a 1977 episode of 'The Tonight Show.' ''From tonight on, I want to be known as Izzy Yiscowitz. I'm a Hasidic jew. Izzie Chaim Yiscowitz. That stands for Chaim the Greatest.'

Crystal also roasted Ali during a guest spot for the fighter's 50th birthday celebration TV special.

SATURDAY NIGHT LIVE:

Live, from New York, it's Sat-Ali Night!

Crystal wasn't the only SNL performer who found Ali's bombastic style perfect for parody.

Here's a 1981 sketch with Joe Piscopo as a reporter interviewing a young Cassius Clay (played by Eddie Murphy) training for his latest fight:

'I'm going to retire from the boxing game healthy, happy, rich and pretty. I'm the greatest fighter of all times!!!' Murphy as Ali says pointing at the camera. 

Crystal and Ali forged a friendship that spanned 40 years. Above Ali jokingly holds up bunny ears behind Crystal as they pose for a photo in 2000 at a charity event

IN LIVING COLOR:

David Allen Grier did his best work as Ali on 'In Living Color' when he played the befuddled champ in a spoof of the movie 'Three Men and a Baby' called 'Three Champs and a Little Lady.'

Grier played Ali (other actors played Mike Tyson and Sugar Ray Leonard) in the skit and has kept his impression part of his routine.

Skip to the 2:50 mark to hear Grier channel Ali on a radio show hosted by MTV News reporter Sway. 

TYSON-ALI: 

It's not quite an impersonation, but who can resist Mike Tyson recalling the time he told Ali he would avenge his defeat to Larry Holmes? Here's Tyson on Conan O'Brien's show.