After releasing three albums between 2008-10, Elvis Costello took a few years off from the studio -- a break that he recently ended by recording a new LP with the Roots.

Roots drummer (and in-demand producer) Ahmir 'Questlove' Thompson opened up to Rolling Stone about the sessions, which grew out of Costello's guest spots on 'Late Night with Jimmy Fallon,' where the group serves as the house band. "After [his] third appearance, we liked him so much we were like, 'Hey why don’t we make a record?'" he explained. "What went from being one song to be released on Record Store Day became 'Why don't we try four songs?' Now we have a brilliant album."

Now the full-length set, which Questlove says is almost finished, is scheduled to arrive in stores in time for Record Store Day on April 20. While remaining cagey about the details, he enthused, "In the whole history of the Roots, I have never bragged on an album first, but I actually love this record."

Costello's new record fits into a crowded Roots schedule that includes making new music with another veteran act: Soul legend Al Green, who's using them as his band on the upcoming follow-up to his 2008 release 'Shake It Down.'