Speaking to VMusic, the knob-twiddler said that "this was a very good and big surprise for me!"
He'd assumed "she would spend only an hour or two in the studio per day and come and see where we were and say, 'Ok I like this, I don't like that. I'll sing this. Bye!' And absolutely not".
Martin continued: "it's not just written on the credits 'co-produced by Martin Solveig and Madonna', we literally co-produced the tracks. I mean, at some point she'd want to choose the sound of a snare drum or a synth and that kind of stuff".