Calgary-based journalist Rebecca Eckler says she is suing the makers of the comedy Knocked Up for stealing her story.

Eckler, author of a memoir about her accidental pregnancy, also called Knocked Up, claims her 2004 book is the unacknowledged inspiration for the film, which had strong box office at its opening this weekend.

Writing in Macleans magazine, Eckler said she is suing Judd Apatow, director of Knocked Up, and Universal Studios, the producer.

The movie, like Eckler's book, is the story of a one-night stand, by a young woman under the influence of alcohol, that results in a pregnancy.

Eckler said if the similarities ended there, she could let the matter go — but they continue, right down to the religion of the father (Jewish) and the career choice of the film's main character, Alison.

"Both my book and the movie feature one night of passion and the nine months that follow. Fine. Whatever," she wrote.

"But what got me was the fact that 'Alison' was an up-and-coming television reporter; in my book, I was an up-and-coming newspaper reporter."

Eckler admitted that it's difficult to prove that any other woman who became pregnant by accident wouldn't go through the same things she did in her book, but she said she feels she must speak up.

Alison is played by Katherine Heigl in the film, with Seth Rogen as the father who has to grow up fast.

Eckler, a regular contributor to Macleans, is also the author of Wiped! Life with a Pint-Sized Dictator.