Earlier today, No Doubt posted a photo to their Twitter page, with the caption simply saying "@NoDoubt and @MajorLazer together". As you can imagine, the photo features Gwen & Co. with Diplo and Switch in the studio (view above).
A few preceeding tweets confirm that they were working on "3 different songs" in "3 different rooms" last night. No Doubt guitarist, Tom Dumont tweeted one of the tracks that they were working on was titled "Push and Shove".
Don't expect too many Major Lazer produced tracks on the new No Doubt LP though. Apparently the long-time ska/pop group have spent most of the year working with Madonna producer, Mark Stent.