"I worked with her before on her album, 'Femme Fatale'. We did a song called 'The Big Fat Bass' and then we talked about working on music for my record. So we made two songs and 'Scream & Shout' was just urgent. It was like put this out now!," he said.
Will.I.Am said that both he and Spears brought the action when it came time to lay down the track.
The artist, who is a coach on the UK version of 'The Voice', said he wouldn't rule out following in Spears' reality TV judge footsteps.
"I've done some mentoring on the judge's house portion on 'The X Factor' America and some on 'American Idol'. So, I wouldn't shy away from those type of things, but you never know.
