Mark Ronson thinks it's ''nuts'' how successful 'Uptown Funk' is.

The 39-year-old music producer - who collaborated with 'Locked Out Of Heaven' hitmaker Bruno Mars on the chart-topping track - has admitted he is completely stunned by the song's international triumphs.

Speaking after the track won Best British Single at last night's (25.02.15) BRIT Awards with MasterCard, he told BANG Showbiz: ''It's just nuts. I didn't even realise we were actually eligible. It's insane.

''This song that started as a jam in Bruno's studio in LA just about a year ago, people have taken it on and love it and it's just nuts.''

Mark - who attended the ceremony alongside his wife Joséphine de La Baume - fought off competition from huge hits including Clean Bandit and Jess Glynne's 'Rather Be', Ed Sheeran's 'Thinking Out Loud' and Sam Smith's 'Stay With Me' amongst others but he is just shocked to be nominated alongside artists of such calibre.

He said: ''What's really cool is when I go to New York and I turn on Hot 97, I hear Clean Bandit and I hear Sam Smith and then you change the station and you hear Calvin [Harris] or Ed Sheeran.

''The singles like that - which are massive all around the world, to be recognised in a group with them feels massive.''