With two rock star parents, it's not surprising that Zuma Rossdale wants to follow in their footsteps.

During an appearance on the Ellen DeGeneres Show September 25, No Doubt frontwoman Gwen Stefani, 42, said her 4-year-old son has been jamming with bandmates Tony Kanal, 42, Adrian Young, 43, and Tom Dumont, 44, quite regularly.

"Zuma's the one who's showing more interest in the guitar," Stefani (also mom to son Kingston, 6, with husband Gavin Rossdale, 46) said. "Since he was tiny, he's always played guitar--well, he doesn't really play guitar, but he thinks he does."

Host Ellen DeGeneres, 54, then played a clip of Stefani's youngest son rocking out on stage during No Doubt's sound check earlier that afternoon. "Oh my God," a delighted DeGeneres laughed. "That's hilarious!"

No Doubt recently released Push and Shove, their first album in 11 years. (Stefani released solo records in 2004 and 2006). Given that they are all married with children, recording new material "was challenging," Stefani admitted.

"We'd get together like three times a week, and I tried all versions -- like, 'Oh, today I'm gonna bring him with me,' and that didn't work," the platinum blonde singer said. "So then I was like, 'Today I'm not gonna see him. I'm gonna work all day, and then I'll be with him tomorrow.' It was just chaos, so that's one of the reasons it took as long as it did."