The 24-year-old Bajan-born singer, who was accosted by a flurry of fans and even kissed on the lips by one, wore a grey T-shirt with "C**TLIFE" emblazoned across it complete with a bullet instead of an "i" in reference to Tupac Shakur's infamous "Thug Life" tattoo.
The star paid homage to the late rapper earlier this year by having "Thug Life" temporarily inked across her knuckles.
Rihanna reportedly visited three recording studios after touching down in the UK yesterday, beginning at 6pm and not finishing until the small hours of 3am when she finally returned to her Central London hotel.
Aside from recording new material and wearing crude T-shirts, Rihanna is currently in the capital for her performance at the upcoming Radio 1 Hackney Weekend.
View other stars in questionable outfits this week below:
Copyright: Rex Features