In October 2011, commuter Lisa-Marie O'Keeffe was excited to spot a familiar face on the Tube. Rihanna was on her way to a gig at the o2. She said the star was telling excited fans to "hold on tight" and was "being very motherly".
Another commuter, Adrienne Amando, said Rihanna was with her minders and manager, saying "she was so gracious and so humble and so lovely, it was wonderful"
More top news
Pictures of today's events unfolding following a major security incident at the Houses of Parliament.
At least two people have died after a knifeman brought terror to the heart of Westminster.
The Cobra committee brings together government ministers with senior officials of the emergency services and security agencies.