George and the Coronation Street actress confirmed their split last month. The break-up was said to be due to the pair's long distance relationship.
However, the Wanted singer has allegedly told friends that he has placed himself on a sex ban while he is touring Australia with the band, in an attempt to reclaim Keegan as his girlfriend.
"Max is serious about behaving himself - in real life and on his phone. He's been telling friends he wants to persuade Michelle to take him back and is dedicated to not having relations with any other women," a source told The Sun.
"It's not going to be easy while the band are on tour.
"They are constantly surrounded by women they're meeting for the first time but Max is committed to the challenge."
The pair began dating in late 2010 and called off their engagement in April, after having continually denied rumours that they had broken up.
Keegan dismissed reports that she had reunited with George earlier this month.