Former Heroes star Panettiere confesses she was so nervous about working with the Beautiful hitmaker, she stumbled over her words and couldn't look Aguilera in the face.

The 25 year old says, "She's one of my favourite singers of all time, she's so incredibly talented. I was actually very nervous around her when we first did the rehearsal. I walked in and... I open the scene with this funny line and I said it so wrong, it didn't even make an ounce of sense!

"I don't know if it was because she felt bad for me, but she started laughing and I was like (cowering in embarrassment). But she's amazing and we had such a great time."

Aguilera features as Jade St. John, a pop superstar with country music dreams, in two episodes in the current third season of the musical drama.