Bruno Mars wishes he had written Rehab by Amy Winehouse.

The track is often referred to as the late singer’s ‘signature song’ and brought Amy worldwide fame.

Whereas Bruno has had huge hits, such as Grenade and Locked Out of Heaven, he is envious of other writer’s talents.

"They Try to make me go to rehab but i say No No No #WishIWroteThat (sic)” he admitted to his Twitter followers.

Since hitting the music scene, Bruno has scored a Grammy Award and his debut album Doo-Wops & Hooligans is certified platinum.

Despite his success, he can’t help feeling he missed out by not coming up with some iconic lyrics.

Among those he is most jealous of are You Sexy Thing by Hot Chocolate and Big Poppa by The Notorious B.I.G.

“I believe in miracles. Since you came along. You sexy thang. You sexy thang you. #WishIWroteThat,” he tweeted.

"Cause I see some ladies tonight who should be havin my baby.... baby #WishIwroteThat (sic)”

The 27-year-old is currently busy promoting his latest album Unorthodox Jukebox.

He has admitted how difficult it is to come up with new material in the past.

"You know how hard it is to write a big song? That sh*t is hard, man. It's so hard to do. Might be one of the hardest things to ever do," he said in an interview with GQ.

"I don't ever want to come out with something safe and get away with, 'It sounds good!' It's got to be more than sounding good."