Michael Caine was walking down London’s Piccadilly one day when he bumped into old friend Charlie Watts, the drummer for the Rolling Stones.

As they chatted, Caine’s cellphone rang, and it was another old friend, actor Roger Moore. He was going to Buckingham Palace to be knighted and was nervous about one aspect of the ceremony. Since Caine was already a knight, Moore asked Caine to walk him through it, and Caine obliged as the legendary drummer stood by, waiting for the call to end.

Caine’s new memoir, “From Elephant to Hollywood,” is that kind of book. A Hollywood fixture for half a century, Caine has known, befriended, worked or partied with everyone from John Huston to Heath Ledger, and has the kind of life where a Rolling Stone waits patiently while he gives James Bond advice on how to become a knight.

As such, this breezy, name-droppy salute to old, un-PC Hollywood is a lighthearted hoot.

As a young actor, Caine’s great friends included Sean Connery — who would pummel four drunks at once if need be — and Peter O’Toole. Caine and O’Toole went drinking one Saturday night, and the next thing Caine remembered was waking up in a strange home at 5 p.m. on Monday. He began to ask what had happened over their two lost days, and O’Toole replied, “Never ask. Better not to know.”

At the Cannes Film Festival, Caine met a great drinking pal in John Lennon. On one particularly sauced evening, Caine found Lennon peeing out the window of a local palace.

“John — you’ve got it on the bloody curtains!” said Caine. “Who cares,” Lennon replied. “They’re rich. F – – – ’em!”

For decades, Caine’s life was a Hollywood whirlwind.

Danny Kaye would invite him over for Chinese food with the likes of Cary Grant and the Duke of Edinburgh, and he’d see Klaus Kinski buying an ax at the local hardware store.

At a party at Billy Wilder’s house, Wilder had paintings stacked against the wall, and Caine accidentally knocked a few over — and “nearly had a nervous breakdown” when he realized they were a Klimt and a Hockney.

While much of the book turns on A-list anecdotes, Caine also touches on Hollywood’s dark side.

Filming “Hurry Sundown” with director Otto Preminger, Caine’s character was called upon to rape Jane Fonda’s.

A nervous Caine asked Preminger for advice, and was told to just do it, and that Preminger would call “cut” when he had enough. Caine did the scene as told, but felt it getting out of hand and yelled out, “I’m stopping.” When he did, Preminger and the crew were “sitting there with wolfish grins,” as “they had long since switched off the camera.”

Less violent but still creepy, Caine and his pal Warren Beatty had a contest where they’d see a girl from behind, and one of them would say, “Beautiful or ugly?” The other would call it, and when the girl turned around, the winner would give the loser five dollars. (Caine says of this, “sexist, I know, but it was the ’60s.”)

They played one time on a girl buying a newspaper in London, and after Caine proclaimed “ugly,” the girl turned around, and it was Candice Bergen. Caine quickly gave up a fiver.

Massive egos were everywhere. Shooting “Victory” with Sylvester Stallone, the “Rocky” actor insisted on only being called to set if his scenes were ready to film. When poor weather caused a three-hour delay one day, Stallone informed the cast that he would make them wait three hours the next day in retaliation. He kept his word.

Every aspect of Caine’s life, good or bad, had a sense of the cinematic. One night, he saw “the most beautiful girl I’d ever seen” on a Maxwell House commercial. Determined to track her down, he even considered flying to Brazil, since he took her for Brazilian. But later that night, he learned that the ad was made in England, and that the actress, who was actually Indian, lived only a mile away.

Caine met the woman, named Shakira, soon after. They immediately began dating, were married in 1973, and remain so to this day.

A former restaurant owner, Caine also co-owned The Canteen in London’s Chelsea Harbor, and had to install extra doors between the kitchen and the restaurant to shield customers from the foul language of his sous-chef, Gordon Ramsay.

But overall, “The Elephant to Hollywood” is at its best conveying an aura of old time Hollywood, from a man who clearly relished that era.

In one especially revealing anecdote, he tells of seeing Liz Taylor at a party soon after Richard Burton had bought her an insanely expensive diamond necklace.

Complimenting her on the piece, Taylor said that it wasn’t real. He asked why she had two bodyguards with her, and Taylor replied — as if explaining to a small child — “if I didn’t have the guards, Michael, everyone would know it was paste.”

Michael Caine

The Elephant to Hollywood

by Michael Caine

Henry Holt and Co.