Reunion band's first single?

Siobhan tweeted last night: "Oh boy, it's a first single!!! We killed it today"

 Officially, of course, she could be referring to her new solo project. But then why the "we"?

 Somebody asked Keisha if her first single was ready. Her reply: "Getting there :-)"  She'd earlier tweeted: "Studio session was soooo dope!!! " Shortly after somebody asked Mutya whether she was speaking to any of the other Babes. Her denial came (as it did in January): "We dnt speak but were kl".

Curious that as a few hours later she was out clubbing with Keisha - and here's the evidence: http://yfrog.com/mnysztej 

Bet they were celebrating the completion of that first single. It's gotta be good! And here's a reminder of just how good it could be: