Johnny Depp and Penelope Cruz's Secret 'Pirates of the Caribbean' Bet

ET's Mark Steines sat down with the stars of 'Pirates of the Caribbean: On Stranger Tides,' uncovering a bet that Penelope Cruz said she'd kept secret until now.

In the midst of praising Johnny Depp for his sense of humor, Cruz leaked that she lost a bet to the actor that had a hilarious consequence, saying, "I had to dress up like Mr. Hanky the Christmas Poo [from 'South Park']."

Cruz went on to divulge that Depp actually had the costume custom made for the actress.

"He made me wear it the last day of shooting and I had to walk around like that," said Penelope. "He took a lot of pictures."

Johnny dons his red bandanna and eye shadow for the fourth time, playing Captain Jack Sparrow in 'Pirates of the Caribbean: On Stranger Tides.' But this time Jack is after a bigger prize than the heart of Davy Jones or a chest of gold coins. Now Jack has set his sights on the Fountain of Youth.

Playing the role as many times as Depp has would seem to pose some difficulty in bringing the freshness that he's been able to conjure for 'On Stranger Tides,' and Depp gave Cruz partial credit for making the movie work so well, calling the casting choice "brilliant."

Cruz also impressed Depp with the athleticism she displayed, shooting action scenes while carrying an extra load.

"She was with sword and baby at that time," Depp said.

Cruz and Depp's characters bicker throughout the entire movie, but this brought Mark to ask whether Captain Jack would ever fall in love.

"I think if Captain Jack found love, real love, he would probably go catatonic," said Depp.

'Pirates of the Carribbean: On Stranger Tides' sails into theaters May 20.