Adele is reportedly due to give birth in September.
The singer only announced her and boyfriend Simon Konecki's big news on 29 June, but it's thought she may have been hiding her pregnancy for 7 months.
'Adele has barely left the house in recent months, so she could keep this to herself for as long as possible,' says a source.
'She stopped exercising a few months ago and since then it's been all about the baby.'
It's been noted that Adele, 24, chose not to fly to the US for the Billboard Music Awards in May, despite winning an incredible 12 categories.
She also refused to talk to reporters or pose for photos at the Ivor Novello Awards in London a week later - she'd turned up late to the event and wore a black baggy ensemble.
A spokesman for Adele told the Daily Mail that he had 'no more information' on the pregnancy.
SEE PICTURES Adele's life story>>
SEE PICTURES See Adele and all the stars at the Brit Awards 2011>>
SEE PICTURE GALLERY Adele takes the Grammys by storm>>
Anna Duff
