Her debut at the Royal National Theatre looked in doubt when she was struck down with the virus on Wednesday.

I absolutely loved it

Lord Lloyd-Webber

McCutcheon's 18-year-old understudy, Alexandra Jay, had to stand in for a warm-up performance on Wednesday night after doctors advised the 24-year-old actress to rest.

But on Thursday evening she was in fine form showing no signs of illness.

She sang all the musical's classic songs such as Wouldn't It be Lover-ly and I Could Have Danced All Night, to huge applause from the audience.

McCutcheon, along with cast members who include Dennis Waterman as Eliza's father and Jonathan Pryce as Professor Henry Higgins, received a standing ovation for their efforts.

In the audience was Lord Lloyd-Webber who described her performance as "fantastic".

"I absolutely loved it," he said.

A spokesman for the Royal National Theatre said earlier that although McCutcheon still felt unwell, she did not want to let people down.

Busy box office

The new production of the famous musical also stars Jonathan Pryce as Professor Higgins and is directed by Trevor Nunn, who has been director of the theatre since October 1997.

The theatre's box office has been doing a brisk trade, thanks to McCutcheon's TV and pop fame.

Preview performances have been well-received

The 24-year-old performer has spent the last eight weeks rehearsing the role of Eliza Doolittle, made famous on stage by Julie Andrews and then on film by Audrey Hepburn.

Press previews of her performance have received rave reviews.

She has also made two pop albums, the most recent of which, Wishing, was released in November 2000, after leaving BBC soap EastEnders, where she played barmaid Tiffany Mitchell.

The musical, written in 1956 by Alan Jay Lerner and Frederick Loewe, was filmed in 1964 with Audrey Hepburn and Rex Harrison.

It was based on the George Bernard Shaw play Pygmalion.