I really see no problem. You said it, friends, fun, paid. Music is also about PLAYing, have fun. I don't know tatu's music but the list of his work shows a broad range of styles. So he seems to be an open minded chap, exploring this and that. I wished MK had shown more of this mindset during his solo years, keeping things fresh, working with different people from different spheres, different producers and so on. I also didn't get the Vince Gill connection.
LE