Rihanna surprised clubbers at a London nightclub by giving out sex advice.

The 'S&M' singer was partying at Whisky Mist in Mayfair after her concert at The 02 arena on Sunday (13.11.11) to celebrate her brother Rorrey's 22nd birthday and after Rihanna led the revellers in a singsong, she took it upon herself to offer some wise words for the bedroom.

She said: "I left home at 16 and had to learn to look after myself. But now we're back friends stronger than ever. Always use a condom."

Generous Rihanna splashed out on 15 bottles of champagne and six bottles of vodka for her brother and other revellers and then allowed Rorrey to continue partying with his friends and a bevy of beauties at her suite at The Savoy hotel.

A source said: "Rihanna is the best big sister. She sorted for all these girls to accompany her brother back to her hotel, along with friends of his too. They had a great time and she treated them like kings."

Although the 23-year-old Barbadian superstar provided her brother with a great time, she disappointed some fans last night (14.11.11) when she arrived on stage at her concert at The 02 an hour late.

Fans took to twitter to complain with one user roroism writing "When I met Beyonce she was everythin & more. @rihanna left me devasted & upset today. So unprofressional. I actually feel like Im guna cry. (sic)"

Lee Latchford Evans from recently reformed pop group Steps added: "Loving Rihanna tonight great performance & show. Shame she was 1hr late. Fans booing is not a good start. X (sic)"