The "Twilight" star revealed in an interview with Black Book magazine prior to the scandal that he would pen tunes for his muse, reported Examiner online.
He also gave an insight into what those songs might sound like, speaking of his pre-fame gigging days, when he would perform at open mic nights to "about three other performers and the bar's waitress".
Pattinson said when he first moved to Los Angeles he would sing at quirky venues like The Rainbow Room on Sunset Boulevard.
Earlier this week, pictures of his girlfriend, 22, kissing 41-year-old "Snow White And The Huntsman" director and married father-of-two Sanders surfaced.
The scandal has led to Pattinson leaving the USD 6 million Loz Feliz mansion he shared with Stewart and the actress is said to have followed suit. They are also said to not be on speaking terms.
Both Stewart and Sanders have publicly apologised.
