Hayden Panettiere performed a surprise striptease for boyfriend Milo Ventimiglia’s thirty-first birthday earlier this month.

The eighteen-year-old Heroes actress, who portrays cheerleader Claire Bennett on the NBC sci-fi hit, devised a sexy cheerleader romp before stripping down to reveal red lingerie, an In Touch Weekly source says.

“Hayden gave Milo an unforgettable birthday surprise by morphing from her bouncy cheerleader character in Heroes to a bump-and-grind striptease.”

“She asked the wardrobe girls to make her a Velcro lined version of the outfit she wears on the show. As she sang ‘Happy Birthday’ to Milo in front of cast and crew during lunch she ripped off the costume to show off her sexy red lingerie. Milo’s face went bright red.”