. >> rose: mark ronson is here, the british producer made his name as a deejay in the '90s new york city the year. uptown special according to "time magazine" has skill and intelligence. uptown funk has been viewed on youtube more than 1.5 billion times. here's a look at uptown funk featuring bruno mars. ♪ hollywood, jackson, mississippi ♪ ♪ girls hit your hallelujah ♪ uptown funk gonna give it to ya ♪ ♪ 'cause uptown funk gonna give it to ya ♪ ♪ saturday night and we in the spot ♪ ♪ don't believe me just watch >> rose: mark ronson, welcome. thank you for having me. >> rose: you said you worked on uptown funk to within an inch of its life. >> yes. what happened with that song is it started off as a jam in bruno's studio. bruno was on the drums, i was on bass, jeff was on the synth. sometimes a jam is a waste of time but i've now and then you hit a rhythm and that one felt great. the jam is like conceiving a baby, anything is possible. it could go this way or that way. >> rose: improvisational. and that's fun and the sky is the limit, and then you get to the point six months down the line