Short but sweet little sex kitten Hayden Panettiere is breast known as a cheeky cheerleader on the superhero show Heroes, and she put her cheerleading uniform to a much different use when she gave her boyfriend, Heroes costar Milo Ventimiglia, a sextra special gift recently.

Allegedly, Milo had a very, very happy birthday on July 8th, when he turned thirty-one. Not only was his gorgeous 19-year-old girlfriend Hayden in attendance, but she was wearing a special version of her rah-rah gear . . . which she ripped off to reveal red lingerie.

Female First reports:

Hayden Panettiere performed a surprise striptease on her boyfriend Milo Ventimiglia's birthday.

The 'Heroes' actress - who plays self-healing cheerleader Claire Bennett in the hit TV show - donned a special raunchy cheerleader outfit and treated her co-star, who turned 31, by gyrating in front of him, before whipping off the costume to reveal sexy red lingerie.

A source said: "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."

Hayden finished her routine by kissing and hugging Milo as onlookers gave her a standing ovation.

When it comes to Hayden Panettiere in her underwear, a "standing ovation" is had by all.