Reese Witherspoon arrives for the 78th Academy Awards on March 5, 2006, in Los Angeles(AP photo)

Reese Witherspoon has sued Star magazine, alleging the tabloid ran a false story saying she is pregnant with her third child.

The lawsuit filed Wednesday in Superior Court claims a story in the magazine's June 26 issue falsely stated that she didn't want producers of two of her upcoming movies to know she was expecting. The story also suggested that Witherspoon, 30, was wearing maternity clothing, according to the lawsuit.

"It is a frivolous lawsuit," Mike Kahane, general counsel to the tabloid's parent company, American Media Inc., said in a statement Thursday. "It has no legal merit and we intend to vigorously defend it and have every confidence that we will prevail."

Witherspoon claims the story harmed her because it suggested she is hiding information from her producers. Being pregnant would affect her ability to perform her duties in connection with those films, the lawsuit said.

"The true facts are that plaintiff is not pregnant, does not have a baby bump and has not otherwise gained weight such that she has had to resort to wearing empire-waist dresses," the lawsuit said.

Witherspoon, who is married to Ryan Phillippe, won an Oscar for her role as June Carter Cash in 2005's "Walk the Line." The couple have a daughter, Ava, born in 1999, and a son, Deacon, born in 2003.