LOS ANGELES (Reuters) - Fans already are devouring "The Hunger Games," the highly anticipated post-apocalyptic drama from Lions Gate Entertainment that reaches movie theaters this weekend.

The movie pulled in $19.7 million in showings just after midnight early Friday in the United States andCanada, Lions Gate said. That ranks seventh among all-time midnight screenings, just behind 2009's "Harry Potter and the Half-Blood Prince," the studio said.

Hollywood placed lofty expectations on "Hunger Games," the film based on a best-selling book bySuzanne Collins about children forced to fight to the death. Sales forecasts for the opening weekend range as high as $125 million-plus, with some box-office watchers comparing its drawing power to the popular "Twilight" vampire romance series.

Last November's Twilight film, "Breaking Dawn - Part 1" grossed $30.3 million in midnight showings. "Harry Potter and the Deathly Hallows - Part 2," last summer's finale of the blockbuster series about a boy wizard, set the record with $43.5 million from midnight shows, according to Hollywood.com.

"Hunger Games" is expected to become Lion's Gate's biggest film opening ever. The company's shares have gained 32 percent in the past six weeks in anticipation.

On Friday, Lions Gate shares fell 2.3 percent to $14.22 in early afternoon trading on the New York Stock Exchange. Evercore Partners analyst Alan Gould, who rates the stock "equal-weight" with a $15 price target, said investors likely were capitalizing on the stock's recent gains by "selling on the good news."

(Reporting By Lisa Richwine; Editing by Ronald Grover and Tim Dobbyn)