Tamsin Egerton is "shaking with excitement" over her latest project Justin And The Knights Of Valour, a 3D animation starring Antonio Banderas and Freddie Highmore.
The 23-year-old plays the love interest of Freddie's character, Justin, but the two actors go way back - all the way back to childhood, when they starred in British fantasy film The Mists Of Avalon.
"I know Freddie as we worked on our first job. He was six and I was 11," Tamsin explained. "We played brother and sister."
In Justin And The Knights Of Valour, their characters begin an unlikely romance after Freddie's attempts to impress Tamsin lead him on a quest to become a dashing knight.
The St Trinian's star has only seen snippets of the children's film so far, but declared that she had every faith in the production crew, which includes The Emperor's New Groove scriptwriter Matthew Jacobs.
"They know their stuff," Tamsin said. "From what I saw of the [film] it looked extremely high-calibre."
"I was shaking in excitement because it was unbelievable."
:: Tamsin Egerton is supporting the Sky Go Movies Express. To experience the new Sky Go service at www.skymovies.com/express.