Photo of Win Butler and Diplo via Butler's Instagram

Last night, DJ Windows 98, aka Arcade Fire's Win Butler, performed a DJ set at the Phi Centre in Montreal for the third installment of his monthly Naive Melodie concert series. Butler was joined onstage by special guests Madonna and Diplo, as well as fellow Arcade Fire member Régine Chassagne. See photos and video from the event below.

Earlier this summer, Diplo and Skrillex (who collaborate as Jack Ü) were spotted in the studio with Butler and Chassagne, but Butler clarified it was not a session; he and Chassagne were "just showing a couple of friends [their] studio." Diplo, however, later told PBS' Charlie Rose that the four were, in fact, working on beats together based on a 20-minute live rehearsal from a recent jam session.

Read "Pop Sovereign: A Conversation With Madonna".

Watch Butler perform as DJ Windows 98 at Pitchfork's SXSW party: