LONDON, ENGLAND - MARCH 15: Justin Beiber (R) unveils his waxwork at Madame Tussauds on March 15, 2011 in London, England. (Photo by Gareth Cattermole/Getty Images)

According to Justin Bieber, he was joking when he challenged Tom Cruise to that UFC cage fight…

He admitted Wednesday, that he was just playing when the paparazzi asked him about it.

The singer, 25, originally challenged Cruise, 56, on Sunday (via Tweet)  to a UFC cage fight.

He quoted, “He’d probably whoop my ass in a fight. . .I’m really skinny right now.  I think he’d probably be out of my weight class . . . He’s got that dad strength.”

Do YOU think Justin was really joking or do you think he watched some of Tom’s old “Mission Impossible” movies and changed his mind? (LOL)