George Clooney once gave 14 of his best friends a million dollars in cash as an expression of gratitude, a close pal has revealed.

Clooney's unbelievable generosity was revealed by businessman Rande Gerber, supermodel Cindy Crawford's husband, in a recent episode of MSNBC's Headliners.

He recalled the story about how the actor invited the group over for dinner and then handed out a briefcase, that contained the surprise gift, to each one of them. Not only did Clooney present them with $1m, he also paid their taxes for the year.

"There's a group of guys we call 'The Boys,'" Gerber explained. "George had called me and 'The Boys' and said, 'Hey, mark 27 September 2013, on your calendar. Everyone's going to come to my house for dinner."

The Out of Sight actor wanted to thank his friends for helping him when he was just starting out in Hollywood.

Gerber said: "George begins to say, 'Listen, I want you guys to know how much you've meant to me and how much you mean to me in my life. I came to Los Angeles, I slept on your couch. I'm so fortunate in my life to have all of you and I couldn't be where I am today without all of you. So it was really important to me that while we're still all here together, that I give back. So I want you all to open your suitcases"'.

"We open it up, and it's a million dollars in $20 bills. Every one of us, 14 of us, got a million dollars. Every single one of us. We're in shock. Like, what is this?" Gerber continued. "He goes, 'I know we've all been through some hard times, some of you are still going through it. You don't have to worry about your kids, you don't have to worry about, you know, school, you don't have to worry about paying your mortgage.

"One [of us] was working at a bar in Texas at the airport, trying just to support his family. Rides a bicycle to work every day. I mean these are guys that took care of George and now he's giving it all back. And George said, 'Not only that, I have paid everyone's taxes so this million dollars is yours.'"

clooney casamigos
Hollywood superstar George Clooney and Cindy Crawford's husband Rande Gerber co-founded the tequila with real estate developer Mike Meldman. Casamigos / Twitter / @casamigos

Gerber, Clooney's partner in his tequila company Casamigos Tequila, is a multi-millionaire himself.

He further revealed: "I pull him aside and said, 'I absolutely am not taking this million dollars. Immediately George goes, 'I'm just going to make one announcement. If Rande doesn't take the million dollars, nobody gets it.'"

Gerber said he donated all the money to charity.

He also added: "This is who George is. That was 27 September 2013. Now 27 September 2014, he marries Amal. That's good karma right there."

Recently Amal and George reportedly handed out personalised noise-cancelling headphones to co-passengers while on board a London-bound plane. It was an advanced apology in case their six-months-old twins started crying on the flight and disturbed the fliers.