(Cover) - EN Showbiz - Bruno Mars says he was nervous to sing F**k You in front of Cee Lo Green, after hed penned the track for the star.

The 25-year-old Hawaiian singer-songwriter shot to international fame with his debut studio album Doo-Wops & Hooligans last year. The charismatic star has since enjoyed a successful musical career, winning Best Male Pop Vocal Performance for Just the Way You Are at the 53rd Grammy Awards. Bruno signed with Atlantic Records in 2009 and became recognised as a solo artist after lending his vocals and co-writing the hooks for the hit songs Nothin On You by B.o.B and Billionaire by Travie McCoy. He also co-wrote the hits Right Round by Flo Rida featuring Ke$ha, and most notably F**K You by Cee Lo Green.

The star has admitted that after penning the track for Cee Lo, he was worried about performing in front of him, as hes always been a fan of his music.

I got signed to Elektra, and he was on Elektra and I was praying, like I gotta work with him! Then we sat down and did some records together and we became friends. Wed just be cracking up at the studio, jokes, jokes, jokes and we finally got extremely comfortable and figured out each others sense of humour, he told Vibe magazine. But after we came up with it [F**ck You] I was a little nervous to sing it for him. All I had was I see you driving round town with the one I love, and Im like F**k you-oo-oo! And he goes I love that! Thats beautiful!

Bruno has revealed he was always admired Cee Lo, 36. The star says that producers thought he was crazy when he wanted to re-create the success of Cee Los 2006 worldwide hit with Gnarls Barkley.

Im a huge fan of Cee Lo. And Crazy was such a special song to me cause it was everything that I was trying to explain at a young age, he added. Just trying to tell producers that I want to do a song like that kinda has a little bit of this and kinda has a little bit of that, and they were looking at me like I was crazy! (C) Cover Media