One of the perks that the Beatles had to get used to in the early days was rubbing shoulders with the rich and famous. One of the first celebrities they met on that first trip to the U.S. was boxer Cassius Clay.

At the time, the 22-year old Clay was prepping for his first fight against heavyweight champion Sonny Liston, which was scheduled for Feb. 25, 1964, at the Convention Center in Miami Beach. His meeting with the Beatles took place a week before, on Feb. 18, at the 5th Street Gym on Miami Beach, which was owned by Clay's trainer Angelo Dundee.

Two days earlier, the Beatles proved to America that they were no fluke with their second appearance on The Ed Sullivan Show, which was filmed at the nearby Deauville Hotel. Before going back to England on Feb. 22, they spent a few more days in the Florida sun, where they were treated like royalty.

"There were two great things in Florida," Ringo Starr said in Anthology. "One: I was taken to my first drive-in in a Lincoln Continental by two very nice young ladies. Two: A family lent us their boat and let me drive. It was a 60-foot speedboat, which I proceeded to bring into port head-on, not really knowing much about speedboats ... They have those pretty rails on the front, and I bent the bugger all over the place. But they didn't seem to mind, you know; they were just happy!"

"Obviously we were having an effect, because all these people were clamouring to meet us," George Harrison said. "Like Muhammad Ali, for instance. We were taken to meet him on that first trip. It was a big publicity thing. It was all part of being a Beatle, really; just getting lugged around and thrust into rooms full of press men taking pictures and asking questions. Muhammad Ali was quite cute ... "

Watch Cassius Clay Conquer the Beatles

If you're picking up on a lack of enthusiasm in Harrison's quote, that's because according to the PBS documentary Made in Miami, the band reportedly preferred to meet and be photographed with the champion Liston. Check out the video above for the full story.

It was all a staged photo-op, and the pictures that emerged – of Clay knocking out all four men with one punch and him beating his chest as they lay on the ground – are undoubtedly corny. But there's something incredible about seeing these five men at a time when they really had no idea of how they would would help shape the world.

Clay won the fight – and the title – by technical knockout when Liston failed to answer the bell for the seventh round. Shortly afterwards, Clay announced his conversion to Islam and that, going forward, he was to be called by his new name, Muhammad Ali.

"I taught him everything he knew," Ringo deadpanned. "That was a thrill, of course, and I was putting my money on Liston, so I really knew what was happening!"

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