Before being watched by 17.3million viewers as the star of the sitcom Two's Company, Sir Donald Sinden was well accustomed to grass-roots theatre.

And the acclaimed actor returned to his roots last week when he paid a visit, in his role as patron of the Finchley Arts Centre Trust, to the walled gardens of The Bothy in Avenue House, East End Road, Finchley.

Sir Donald was at the Victorian-era folly an open air theatrical performance venue to celebrate the news it had been awarded a £418,000 lottery grant. The caramel-voiced thesp appeared instantly at home.

"Have I ever played any venues like this? I have played more village halls in Kent and Sussex than any other actor alive," said the star of stage and screen.

Sir Donald, who can count classic war film The Cruel Sea and the antiques-themed sitcom Never The Twain on his crowded CV, became involved with the project at the suggestion of a friend at the Royal Shakespeare Company. A keen supporter of the arts, Sir Donald was surprised The Bothy had previously escaped his notice.

"I'm shocked. I didn't even know this place existed. I've been living round the corner from here, in Hampstead Garden Suburb, since 1954 and I have never come across this wonderful place.

"It's marvellous," he said.

With aid from celebrity patrons such as Sir Donald and Only Fools and Horses star David Jason, The Bothy aims to raise the £500,000 needed to give the mock fortress a major revamp.

Two large studios, three meeting rooms, together with foyers and catering facilities, are in the pipeline, turning an outdoor performance space and two derelict courtyards into a fully-fledged arts centre.

It is also hoped that some lessons taught at the Hampstead Garden Suburb Institute in Central Square will be relocated to The Bothy, as well as courses from Middlesex University.

If the money can be raised, the project is pencilled in for completion in late 2004.