The singer wowed audiences with a rendition of her latest single Only Girl (In The World) on the ITV show.
Dressed in a short pink dress and striking head-gear, RiRi also showed off her matching underwear and long pins.
As she sung, her dancers indulged in a giant food fight behind her.
Her performance won praise on Twitter with fans raving on the social networking site about how 'hot' she was.
One user hayleycalder said: 'Woaaaaah @rihanna was smokin' hot on #xfactor, I have a girl crush on her.'
BethEchelon added: 'WOW...Rihanna dnt mime and sounded gr8...that's a change for xfactor.'
ZaraLouU said: 'Rihanna's performance was wicked!'
Idk if it's just me, though.
