Miss Fisher will perform alongside her heroine Ruthie Henshall

The singer, who won the BBC's How Do You Solve A Problem Like Maria show, will perform at the festival's musical theatre night alongside Michael Ball.

Organisers said it was likely the performance would be Fisher's only one in Wales this year.

Girls Aloud will also be performing at "Bryn-fest", which opens on 24 August.

Fisher, from Pembrokeshire was recently forced to take a two week break from the West End production of The Sound of Music because of damaged vocal chords.

She has since returned to her role at the London Palladium but has reduced the number of performances on medical advice.

Fisher's performance will be part of the Faenol Festival's The Hills Are Alive night.

She will sing alongside Michael Ball, who performed at the first Bryn Fest in 2000, and Broadway star Ruthie Henshall. They will be accompanied by the Faenol Festival Orchestra.

Fisher said she was especially excited to be singing with Henshall, who is one of her musical theatre role models.

"Home crowd"

"I'm really looking forward to performing at the wonderful Faenol Festival with Bryn and to singing to the home crowd again," she said.

The Hills Are Alive gala forms the third night of the eighth Faenol Festival, which takes place in the grounds of the Faenol estate.

It follows an opening night headlined by Girls Aloud along with X-Factor winner Shayne Ward and R&B singer Jamelia.

Bryn Terfel himself will be performing in the opera gala on the Saturday night before the festival closes, as always, with a Welsh rock and pop night.