Troubled pop star Britney Spears has fuelled speculation she is pregnant again, after sneaking into a clinic for a health check up.

She went to the clinic before actor Mel Gibson, 52, took her on holiday to Costa Rica, reports thesun.co.uk.
'The 26-year-old was spotted with an apparent bump recently and spent two hours at LA's Kerlan-Jobe Clinic,' a source said.
But the centre specialises in sports injuries, not pregnant women.
'Despite daily workouts, she has put on a lot of weight in recent weeks. She isn't saying if she is pregnant, but she is taking medication, which has affected her weight. Living with her dad - a chef - means she has piled on pounds. She is extremely paranoid about her body at the moment,' argued the source.
Spears is also believed to be struggling with her weight after she stopped taking Adderol, a stimulant prescribed for attention deficit disorder and used by women to keep hunger under control.
Marty Brenner, an addiction specialist, said: 'Weight gain is a common side effect.'
Britney flew to the 'Braveheart' star's 13 million pound ranch with his wife Robyn and her dad. The unlikely pals were neighbours in Malibu, California.
They are set to return next week.