Rihanna was seen leaving Ashton Kutcher's house at 4 am, according to the Sun.

The singer apparently spent quite a few hours with the Two and Half Men actor and that in denim pants.

"It has been a while since Ashton was getting late-night visits from pretty girls. He has been on his best behaviour, but when Demi finds out, you can only imagine what she will think. She is old enough to be Rihanna's mum," a source was quoted as saying to the Sun.

Rihanna recently recorded a song with her ex-boyfriend, Chris Brown, creating rumours of her getting back with him. Ashton Kutcher separated from his wife Demi Moore amid allegations that he cheated on her.

Rihanna arrives for the BRIT Music Awards at the O2 Arena in LondonReuters