Photo: WENN.com

Pink poked fun at US r&b star Usher during her headline slot at last night's iTunes festival gig, laughing at how sweaty he got at his own show earlier this month.

The US star, who is currently in the UK Top Ten with her comeback hit, made the joke at her first UK gig in two years, referencing the other artists who have performed at this year's London event.

"I saw some photos backstage of the other performers backstage," she told the crowd coyly. "And I am not sweating as much as Usher."

She added: "There's something really unattractive about a man in a dress shirt sweating so much."

During the show she revealed she kept lyrics to her songs on her mobile phone and restarted her track 'Who Knew' after a shaky start to the 2006 hit. She also told the audience that she was backing Barack Obama in the upcoming US presidential elections.

Pink also offered to resuscitate a fan who over heated at the Camden Roundhouse gig, saying: "Is the girl who fainted OK? Don't do that. I'm a mum now. I know CPR."

Pink performed hits including 'Mr President', 'Family Portrait', 'Just Like A Pill' and 'So What' at her iTunes Festival gig. She also performed new track 'True Love' - a duet with Lily Allen, who sadly did not join the star on stage. Pink was supported by rising US band, Walk The Moon.

Watch Pink's Lily Allen collaboration below.