Dad, you're so embarrassing! Ashton Kutcher and his former That '70s Show costar Danny Masterson joined forces with James Corden on The Late Late Show on Wednesday, March 30, to debut their totally amazing new dad band!

Introducing the bit, Corden explained to his audience that he's a huge boy band fan. "I love them all, I love One Direction, the Jonas Brothers, the Backstreet Boys and, of course, the greatest boy band of all time, O-Town. But boy bands don't go away, they grow up. They start families and ultimately they become dads. They're not boy bands, they're dad bands," he continued, before welcoming his next musical guests, the Puff Daddies, singing their song "I'm a Dad."

The unsuspecting crowd cheered the band, and then went wild when Kutcher, 38, and Masterson, 40, took to the stage with the show host, plastic dolls strapped into baby carriers on their chests, pushing strollers.

"When I talk about my baby girl, I don't mean you," sang Kutcher, before the three of them broke into a totally stunning choreographed dance routine around their baby props.

"I'm a dad," the trio warbled, not particularly tunefully!

Later in the show, the two former castmates reminisced about their wild partying back in the days that they were filming their hit sitcom.

"This was pre-TMZ, pre–cellphone cameras. You could wile out and nobody was going to take your pictures," Kutcher recalled.

"I have more photos of commando Kutcher here, naked in a club, than anybody," joked Masterson.

Watch the duo's hilarious dad band performance in the video above.

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