London Fire Brigade says Rihanna was among 300 people evacuated from a hotel after a fire in an elevator shaft.
The singer, 24, tweeted news of the fire, posting a picture of a fire engine and the words: "Roamin da streets since 6am! Fyah in da telly."
The fire brigade said the alarm was raised at 6:22 a.m. and 10 firefighters dealt with the blaze on the seventh floor of the luxury Corinthia Hotel.
There were no reports of injuries.
Rihanna performed Sunday at the outdoor Hackney Weekend concert in London.