Grunberg, along with House star Hugh Laurie and Desperate Housewives actor James Denton are part of the celebrity group Band From TV. They scored a download hit last year with a cover of Cab Calloway's jazz classic 'Minnie The Moocher'.
Grunberg insisted that he would take a role in a Gervais project as long as the British comic promised to perform with the band.
"Ricky's always asking me to do stuff. But I want him in my celeb band," Grunberg said.