The `Twilight Saga` actor - who plays vampire Edward Cullen in the film series - was an aspiring musician before he found success as an actor, but admits he has a slow work rate.
He said: "I write a song every six months. I never write a diary. I think that`s why it takes me so long. You have to summarise your personality changing."
The actor, who plays piano and guitar as well as singing, has previously had two tracks he has performed, `Never Think` and `Let Me Sign` - both of which were written by other people - included on the first `Twilight` soundtrack.
They were reportedly included by the film`s director Catherine Hardwicke, initially without the British hunk`s knowledge.
Robert has previously said he sees music as his "back-up plan" if being a film star fails, and that he believes he will be famous when he-s dead.
He said: "I am sure I`ll be one of those artists that people don`t pay any attention to while I`m alive, and when I am dead people will go yeah, man, that was a work of art."