Singer Lady Gaga was hospitalised six times last year because of her extreme dieting, which saw her lose as much as 20 pounds between fittings for costumes.

The 'Bad Romance' singer's former tour manager, David Ciemny, claims she would binge on junk food such as cakes and sweets, then not eat for weeks to fit into her costumes, once losing 20 pounds between fittings for one of her outfits, reports femalefirst.co.uk.

Describing her condition, Ciemny says in Maureen Callahan's new book 'Poker Face: The Rise and Rise of Lady Gaga': 'When I say she was sick, I mean physically and mentally.'

Talent scout Wendy Starland added: 'The pressure on her to lose weight was very high.'

Despite the six hospital stints, the 24-year-old star's health problems have continued into 2010, with her being forced to cancel four US shows in January suffering from an irregular heartbeat, brought on by exhaustion.

She also broke down in New Zealand in March and has recently tested 'borderline positive' for Lupus, a tissue disease which killed her aunt.