Rihanna: 'Diamonds' World Tour Rehearsal - Watch Now!

Rihanna shows off her long legs in a slit dress while attending the Rihanna for River Island Collection Launch at the Oxford Street River Island store on Monday (March 4) in London, England.

Earlier in the day, the 25-year-old entertainer was spotted donning a white jacket while heading to the launch.

PHOTOS: Check out the latest pics of Rihanna

The night before, Rihanna rocked a white ensemble while arriving at LAX Airport for a departing flight.

Check out a newly released video below of Ri rehearsing for her upcoming Diamonds World Tour, which is set to kick off on Friday (March 8) in New York!

25+ pictures inside of Rihanna arriving at the Rihanna for River Island Collection Launch…