A rep for British heartthrob Robert Pattinson is refusing to comment on rumors that Rob’s Twilight co-star — and allegedly love interest — Kristen Stewart is pregnant with the star’s baby.

Whispers that the 19-year-old is with child began when Australian tabloid NW Magazine claimed Kristen asked a friend to purchase a pregnancy test after an encounter with Pattinson, 23.

“She was worried about someone seeing her at the drug store. She’s very nervous about the whole situation,” a source told the mag over the weekend. “When she worked out she was late, she obviously started to thinking that she could be pregnant. And because of the timing, she thinks Rob could be the father.”

Pattinson’s rep finds the rumor too silly to dignify a response, “We don’t comment on anything like that.”