Singer Rihanna concluded her world tour with a performance at O2 Arena in south London on Wednesday night. She has been touring major cities since June this year to promote her album "Talk That Talk".

The 23-year-old singing sensation was caught yawning during her show at O2, according to a Maire Claire report.

The News Qoud reports that the Barbadian singer admitted that her busy schedule is taking its toll on her energy. She arrived for the live show 30 minutes late.

In past two years the singer has been travelling to different cities to promote her back to back albums "Loud" and "Talk that Talk" and performed more than 100 shows in 2011.

She was booed in Belfast for arriving late. Reports say one man in Lisbon used racial words against her when she was visiting the city. During her performance in the city, Rihanna threw up on the stage.

Fans were reportedly not amused with the singer's performance.

Pop singer Cheryl Cole has congratulated Rihanna in her twitter page after the completion of her tour.