The pair have teamed up for new single 'Scream And Shout' and shot the accompanying music video in Los Angeles back in October.
The clip will receive its official debut during The X Factor USA - on which Spears serves as a judge - on November 28, and appear on VEVO shortly after.
"Working with an artist like Britney is the reason I love making music," will.i.am said in a press release. "She loves music as much as I do. And I am so proud of this new song.
"This is the most exciting song I've worked on in a long time."
Spears added: "There are few people on the planet who inspire me like will.i.am does. I couldn't be more excited to work with him again. I can't wait for people to hear the song and see the video."
'Scream And Shout' - which has been lifted from will.i.am's new solo album #willpower - is available to download now in the US.
A release date for the UK has yet to be announced.
Listen to will.i.am and Britney Spears's new single 'Scream And Shout' below: