Dudley Moore revealed his illness in September

At the start of the half-hour reading, Moore, 64, had difficulty speaking and looked disoriented. But after about 10 minutes he began to ad-lib lines and nod his head in time with the music.

Before he was taken away in a wheelchair, he said: "It was marvellous to be back on stage - just wonderful."

He went on to attend a fundraising event to launch his Dudley Moore Research Fund, created to find a cure for PSP.

In September Moore, best known for his partnership with Peter Cook and the Arthur films, announced he had progressive supranuclear palsy - PSP - an illness similar to Parkinson's disease which makes it hard for him to walk, speak and eat.

He is now undergoing therapy at a clinic in New Jersey.

The event was also a welcome appearance for Julie Andrews. The Sound Of Music star has not sung in public since a 1996 operation to remove nodules in her throat.

She read a story written by a 19-year-old concert winner, and told reporters she felt fine.