Rihanna sexes up the Tube

Perhaps the star was just making the most of the unseasonably warm British weather.

Earlier in the day she had tweeted: "The weather in London is unreal #LilMissSunshine."

Rihanna is becoming a bit of a regular on the Underground — opting for Britain's public transport system on a number of occasions over heavy London traffic.

Last February she was spotted on the Tube on her way to a BRIT awards rehearsal where she was performing.

And in October she travelled to her own concert at the O2 on the Jubilee line.