Photos: Here's what David Beckham thinks of Justin Bieber's underwear ad

Battle of the bulges?!!!
David Beckham isn't worried about Justin Bieber's new underwear campaign outshining his sexy H&M ads.

The soccer stud has now weighed in on the Biebs' recent debut as the face and body of Calvin Klein skivvies.

"Not bad, not bad, not bad," Becks said to an E!Online source of the pop star's strip down when he caught up with him last night at the U.S. launch of his new single-grain Scotch whisky, Haig Club. "He looks good in his underwear ads. He looks very good."

"So do you," said the source.

"Thank you, but I'm slightly older," Beckham said, laughing.

Hard to believe, but the father of four is actually turning the big 4-0 this year (May 2 to be exact).