Mucca makeover: Has busty Heather Mills had a bit of a lift?

Squeezed into a tight grey vest Heather Mills left little to the imagination as she walked through Heathrow Airport tonight.

It may have been a particularly good bra, but her pert, ample bosom prompted onlookers to question whether she had undergone cosmetic surgery.

However, in her autobiography, Out on a Limb, Heather Mills claimed she had undergone a bust reduction in her 20s, going from a bra size 34E to a 34C.

Goodbye Heather: Miss Mills was heading for New York from Heathrow Airport

Following a messy divorce battle with her former husband Sir Paul McCartney, Miss Mills received a settlement of £24.3million earlier this year.

And she seemed in high spirits as she headed off to New York to make a considerable donation to a children's charity in the Bronx.

One onlooker said: 'She was in a good mood. She said she was going to donate $1million to a charity in the Bronx which helped disadvantaged children.'

Plumped up: Miss Mills' cleavage looked considerably larger today, left, than in recent photographs

Yesterday the Mail revealed that Miss Mills is suing her former publicist Michele Elyzabeth for more than £250,000 for breach of confidence and falsehood over newspaper allegations about the former model's failed marriage to Sir Paul.

Miss Mills, mother to the ex-Beatle's four-year-old daughter Beatrice, launched the High Court Action against her former employee following Elyzabeth's claims that Heather was obsessed with money and fame.

Sir Paul met Miss Mills at a charity event in 1999 just a year after Linda died from breast cancer.

Despite his children's serious misgivings about his new love, he wed the former model in 2002 at the17th century Castle Leslie in County Monaghan, Ireland.

The couple had daughter Beatrice a year later but announced their separation in 2006 initially blaming press intrusion.