Dave Grohl appeared on the Late Show with Stephen Colbert last night with his mom, Virginia, to promote her new book, From Cradle to Stage: Stories From the Mothers Who Rocked and Raised Rock Stars. And like most moms, she did her best to embarrass her kid by bringing along a series of items from Grohl's childhood, from an early class picture to his sixth grade report card.

"At what point did it occur to you that he might be a rock star?" Colbert asks after showing the class photo.

"I didn't know he was going to be a 'rock star,'" Virginia says. "I knew he was going to be a musician. I knew really early he was going to be an entertainer. I have the feeling that some of you have it in your blood somewhere; you just start out being goofy and being silly and making people laugh and that's the way he was."

Colbert then pulls out Grohl's report card Virginia brought with her with multiple categories like "Respects Authority" and "Accepts Responsibility" checked off as either "unsatisfactory" or "needs improvement."

"How long is this segment?" the Foo Fighters frontman asks, checking an imaginary watch.

It wasn't all laughs though; on a more somber note, Colbert asked about the suicide of Nirvana frontman Kurt Cobain and how it affected her as a mother.

"It was such a dark, sad time," she says. "David came home after that so we all sort of had to regroup. We talked a lot... We've always been able to say everything to each other. But that was a particularly sort of incredible time. It's hard to express."

TMZ also caught up with Grohl and his mother while in the midst of her book tour. The rocker beamed on his mother's writing after years of being a public school teacher, but then mockingly teased reporters when they asked Virginia if he was a good kid by rushing the camera, blocking it with his hand and stating "No comment." Watch the TMZ interview here.

Virginia Grohl's book, From Cradle to Stage, which also features anecdotes and insights from the mothers of other famous musicians, can be ordered via Amazon.

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