03/10/2008 AT 09:45 AM EDT
Lisa Marie Presley's lawyers are suing British newspaper the Daily Mail
after it published an article suggesting that the singer had developed an "unhealthy appetite" and "has gained weight like her father Elvis."
Presley, 40, revealed the real reason for her expanding waistline – announcing her pregnancy
to PEOPLE on Thursday – and lashed back at the media on her MySpace Celebrity blog
. "I have had to show my cards and announce under the gun and under vicious personal attack that I am in fact pregnant," she wrote.
Her lawyer, Simon Smith, issued a press release announcing the libel claim. In the release, Smith said: "My client is deeply upset and offended by this article, especially as it was widely published just as she and her family were meant to be celebrating her happy news."
A Daily Mail
spokesperson responded in a statement: "The first indication we had of Ms. Presley's complaint was on Friday night when we were served with a writ without any prior warning. We are investigating the matter."
As for her chances of winning the claim, "England has a long tradition of treating mere vulgar abuse or opinion as a serious slur on a person's reputation," Mark Stephens, leading London media law expert at law firm Finers Stephens Innocent, tells PEOPLE.
He speculates that "for an observation that would not be actionable in the USA, she will undoubtedly be recovering damages in London."
With reporting by PETE NORMAN