Bruno Mars' eclectic sound makes him difficult to market.

The 'Locked out of Heaven' hitmaker struggled to get a deal early in his career because record companies didn't know where to target his eclectic sound.

He said: ''That's been the struggle since I started. That was why I couldn't get a deal, that was why a lot of record executives said they didn't know how to market me, because who do they market it to?

''Is it young fans? Is it old fans? Is it urban music? Is it rhythmic music? Is it pop music? Is it rock music? They didn't know what lane they could push the brand to.''

The wide spectrum of influences might surprise fans of the 27-year-old singer's debut album 'Doo-Wops & Hooligans,' but he's always wanted to widen his scope, and is more comfortable with the sound of his second album, 'Unorthodox Jukebox'.

Bruno revealed: ''Being influenced by doo-wop on my first album - with classic love songs, 1950s, my love for that - the pompadour, the suits - I have a passion for that era. But that's not everything that I listen to. That's just something that heavily influenced me when I was a kid.

''[The new album] is more of me. This album is more the whole of everything I love, the music I love to dance to, the music I love to listen to with my girl; good music that I just want to sing. Things that I want to say that I've always wanted to say.''