While A-list guest star Britney Spears didn’t make it to the How I Met Your Mother bash at the Palihouse in L.A. this weekend, our spywitness at the event heard plenty of chatter about the troubled pop star’s time on set.

The show’s star Neil Patrick Harris said he was surprised that Brit was rather quiet. “When she was with us, she
 was rather shy and intimidated,” he explained. “Probably because she doesn’t have a lot of acting experience, especially sitcom experience.”

And as for reports that the 26-year-old mother of two was a nightmare on the set, Neil said, “I wouldn’t call her a nightmare. She’s living
 one.”

While Brit might have been surprisingly quiet around the set, Neil admitted that the hysteria surrounding her even made its way past studio security.”When she’s on set, it’s kind of chaotic, hectic,” he explained. “Even though she was quiet and behaved… She brings that energy with her.”

WENN