Jamie Cullum is working on material for the follow-up to his Verve debut, "Twentysomething."

Jamie Cullum is working on material for the follow-up to his Verve debut, "Twentysomething." That album has sold more than 2 million copies worldwide, according to Cullum's management, including 287,000 in the United States. The United Kingdom accounted for more than 1 million in sales.

"I'm working with a few different architects of sound," Cullum tells Billboard. "I've been hanging out with Dan the Automator, I'll be hanging out with the Neptunes. I've been writing a lot with my brother. I've been at home behind my computer making sounds and behind the piano and just cooking a lot and just generally feeding my imagination for the new record."

Cullum says he doesn't expect the set to include the mix of standards and originals featured on "Twentysomething." "It will be a progression, but there will be a very close link to the last record," he says. "To be honest, we have so much material, I don't know what it's going to sound like."

As previously reported, the artist first worked with the Automator last fall when he guested on Handsome Boy Modeling School's new Atlantic album, "White People." He appeared on the track "Greatest Mistake" alongside Hall & Oates' John Oates and Tarnation's Paula Frazer.

While he works on new ideas, Cullum is booked for appearances on April 29 at Jazz Fest in New Orleans and the following day at the Coachella Valley Music & Arts Festival in Indio, Calif.