Fans livid with Rihanna`s `slurry lip-synching` Singapore concert

Washington: Rihanna`s fans slammed her performance at the F1 Grand Prix in Singapore for being `disappointing`, on Twitter.

Fans accused the 25-year old Barbadian recording artist of being drunk and high on weed, and even `lip-synching` during the show, Radar Online reported.

Recently, the `Diamonds` singer was criticized for posing with an endangered primate and visiting a live sex show during her vacation in Thailand.