Niall sees the purchase as his first step on the property ladder and he plans to invest more of his earnings from the group into more houses.
A source told the Daily Mirror newspaper: ''After marrying Rochelle, Marvin's beloved pad was no longer needed - so he put it on the market and it was quickly snapped up by Niall.
''He loves the place and was determined to get on the property ladder. He hopes it's the start of a proper housing portfolio - especially now he's not short of a few pounds.''
A source told the Daily Star newspaper: ''Selena thinks Niall is very cool and finds his Irish accent really sexy.
''They've been chatting to each other on her private Facebook account and text each other.
''There's a real spark between them.
''They both lead busy lives but Selena would love to get together with Niall next time they're in the same country.''