Lisa Marie Presley plans legal action against the Daily Mail newspaper after she claimed media comments about her weight forced her to reveal she is pregnant.
Her lawyer Simon Smith said Presley was "deeply offended and upset" by the claims, which featured in numerous tabloid newspapers.
The BBC reports her representatives have filed a libel claim against Associated Newspaper's the Mail's parent company, in the high court in London.
Pictures of the 40-year-old singer and son of rock legend Elvis Presley were shown next to suggestions she had a weight problem like her father.
Her growing tummy is not the product of excessive eating but rather the fact she is pregnant with her third child, she revealed on her MySpace page.
But Presley, less than happy about having to open up her personal life to the media, says she had no choice in the matter.
"You know if you were pregnant and you felt you were expanding uncontrollably by the moment as a result, and the worldwide media started badgering and harassing you for it, plastering you everywhere in an unflattering light, you would be mortified as well," she wrote in a statement on her MySpace page.
"After being the target all week of slanderous and degrading stories, horribly manipulated pictures and articles in the media, I have had to show my cards and announce under the gun and under vicious personal attack that I am in fact pregnant."
The latest addition to the scientologist's family is her first with current husband Michael Lockwood, the respected music producer.
She had her first two children with Danny Keough, beginning 20 years ago, and has subsequently been married to Michael Jackson and Nicolas Cage.