Hannigan: 'Britney is fantastic'

How I Met Your Mother star Alyson Hannigan has praised Britney Spears following her recent cameos on the show.

Producers are reportedly keen for the singer to become a permanent fixture on the CBS series after her two guest appearances earned high ratings.

Spears made her second cameo as doctor's receptionist Abby in an episode which aired in the US on Monday.

Hannigan, who plays Lily Aldrin, revealed that she would be happy for Spears to return, saying: "She's fantastic and just a really, really sweet girl."

Talking about the media frenzy surrounding the popstar's appearance on set, she said: "The first episode was a big hoopla. A helicopter followed her into work and people were taking pictures of her off the parking structure. It was pretty crazy.

"But the second time they moved her trailer to a more isolated location and the paparazzi sort of left her alone, I guess. Is the top of her head is it really that interesting?"