Johnny Depp has worked with some Hollywood legends in his time.

But the Pirates of The Caribbean star once opened up about the craziest actor he's ever starred alongside.

Speaking at the Santa Barbara International Film Festival a few years back, Depp was asked about some of the icons he's met during his career, discussing his experience with Marlon Brando.

He then moved onto Al Pacino, who he worked with on the 1997 film Donnie Brasco.

In the movie, Depp played an undercover FBI agent, who infiltrates the Bonanno crime family in New York City during the 1970s.

One of the characters he gets close to during his time is Lefty Ruggiero (Pacino), who he forms a close bond with.

Depp said he was pretty nervous before meeting Pacino, I mean, who wouldn't be, he's an icon.

And he told an audience during a Q&A that he was shocked with just how unhinged he was in real life.

Sony Pictures

"I'm going to work with Pacino," he says. "I'm thinking not gonna get lucky twice. There's no way, this guy's gonna hand me my a*s.

"Cause he looks like the kind of guy who's gonna hand you your a*s. It's Al Pacino.

"So I was fully expecting it, and I'm like psychotic, I can't stand not being able to joke around on set and things like that.

"So I started pulling the gags on Al, and that was the moment I realised he was absolutely out of his mind - I mean, he's certifiably insane."

He added: "I wouldn't spend a night anywhere near his house."

And he even confronted the Godfather star about it.

Santa Barbara International Film Festival

Recalling a day on set, Depp said: "We're about three weeks into shooting, and I said, you know, we're on the docks and Brooklyn.

"Finally, I just couldn't take it anymore. I said, 'Hey, you know, here's the funny thing now, the one thing that I never expected or imagined was that that you're actually, I mean, you're actually certifiably insane'.

"He gave probably one of the most perfect comedic bumps that I've ever seen - 'Oh, yeah, oh, yeah, oh, yeah. You didn't know that?' I said, 'No, I didn't, actually I didn't, really'. He said, 'Oh, yeah'

"And then he just sat there, the most beautiful f**king execution of timing, he just went, 'You're pretty f**king strange yourself'."