Gwyneth Paltrow was interviewed in UK magazine Look (30 March issue) and of course is asked questions about her friend Madonna:

Your best friend Madonna and you both use the same trainer - and Madonna's got some muscles! Does that spur you on?
Oh God, yeah. She's so dedicated, and she looks great on it. She's so damn good at it, you sort of want to be like her. And she's a task master - there's no slacking, no finishing early. In fact, she always makes me do that extra half hour!

You guys are so different, and yet you're such good friends....
I know what you mean. She has the drive and strength I'll never have. But there is a side to her that's very soft and lovely and that's the side we connect more. In private we're more similar than you'd think, but yes, definitely out in the world we're very different from one another.

Come on then, shed some light on the secret world of Madge and Gwyneth....
For starters, I'm such a typical Libra, it's not funny. I can't make a decision about anything - like where to eat, then what to eat, what film to watch. But the worse is what to wear! It drives a certain someone mad!

Sources: Look, Madonnalicious