“Twilight” star Robert Pattinson has a weakness when it comes to women, and gal pal Kristen Stewart doesn’t quite measure up on one score.

Stewart, 21, is petite at 5-feet 6-inches tall and weighs less than 110 pounds. That doesn’t leave much to fill out her lithesome frame, or measure up to Rob’s fantasy.

“Here’s a line from Guy de Maupassant,” an interviewer asked him recently. “‘The essence of life is the smile of round female bottoms, under the shadow of cosmic boredom.’ Any thoughts?”

“That is an absolutely true quote,” Rob replied. “Round female bottoms are very much a miracle.”

de Maupassant wrote the classic novel “Bel Ami,” about a young journalist who beds rich socialites to climb the rungs of society. Rob stars in a movie based on the book.

He told French magazine Madame Figaro that he also loves ladies in haute couture like Chanel and Proenza Schouler.

In yet another interview, this one with Elle, Rob also reveals the women he admired while he was a young teen.

They include supermodel Kate Moss, who is now 37, and actress Linda Blair, now 52, who was a ’70s heartthrob.

Blair is best known as the possessed child, Regan, in the 1973 blockbuster “The Exorcist.”

“I was always obsessed with Kate Moss….On my bedroom wall I had a poster of Linda Blair and Kate Moss,” he said.

Pattinson also revealed that he had a crush on Jane Fonda and Ellen Burstyn growing up.

Rob is busy promoting “Water for Elephants,” which co-stars Reese Witherspoon and shooting “Breaking Dawn Parts 1 and 2,” the final two films in the “Twilight” series.

The lanky, 6’1″ Robert, who has done nude love scenes, worn makeup and donned uncomfortable colored contact lenses for his film roles, draws the line at dancing.

“I guess if you’re constantly in public, you’re not embarrassed about anything, but dancing is my Achilles’ heel — I don’t even try,” says Pattinson.

“It’s like, ‘Come on, dance!’ [and I’m like] ‘No, I’m not getting up!’ I can freestyle by myself with no one watching. I’m a great dancer then.”

Breaking Dawn, which co-stars Stewart and Taylor Lautner, comes out this November.