Kenny RogersKenny Rogers knows when to hold 'em ... and hold 'em ... and hold 'em ... and hold 'em ...

According to dealbreaker.com (via GAC), the country icon was recently paid $4 million to perform at a birthday party for New York hedge-fund manager Raj Rajaratnam, who's a big fan of Kenny's classic hit, 'The Gambler.' Such a big fan, in fact, that the billionaire requested the song 12 times during his party. After a dozen performances of 'The Gambler,' Kenny folded, reportedly refusing to sing it again.

Ironically, Rajaratnam was arrested last week, charged with conspiring to use insider information to inflate his personal bank account. He was brought down by his own colleagues ... and we're guessing they just might have been at that birthday party.