Here’s proof that vampires aren’t invincible. Twilight star Robert Pattinson was battling the flu over the weekend. An insider tells BettyConfidential that the Brit had a busy time with the ladies last week, and ended up paying for it when he came down with the flu.

Our Twilight source reveals, “Robert and one of his guy friends ran to the Gelson’s [supermarket] on Laurel Canyon Boulevard on Thursday night to pick up some cold and flu medicine. He wasn’t feeling good and wanted to try anything to nip it in the bud. He’s too busy to be sick!”

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Robert’s action-packed week began with a photo shoot for Vogue with his Remember Me co-star Emilie de Ravin at the Los Angeles County Museum of Art. The following night the 23-year-old enjoyed a romantic dinner with his Twilight co-star and love, Kristen Stewart, at Gjelina restaurant in Venice Beach.

“Kristen and Rob keep it casual and quiet and Kristen refuses to go anywhere unless she’s confident they won’t be spotted,” the insider says. “She won’t do anything in Hollywood, but she and Robert will drive over an hour to have a quiet dinner for two. It’s difficult and Rob is better about ignoring the press and paparazzi and he will go out no matter what.”

After dinner with Kristen, he headed — alone — to Dimples karaoke bar where he met up with Katy Perry. But all the fun and games caught up with him. “He’s sick and taking medicine but he’ll be back out having fun fast,” the insider says. “He has very little free time between work and promoting movies so he likes to hang out with his friends as much as possible!”

Would anyone like to volunteer to take him some chicken soup?

 Magazine and newspaper reporter Kelly Will has written celebrity columns for the New York Times, the New York Daily News and the New York Post. Follow her on Twitter at twitter.com/misswill.