Diana Rigg, looking gorgeous in a turn-of-the-century long dress and piled-up hair, stepped elegantly into a gondola and bobbed down out of sight. A coffin was placed on a trellis above her - and Di carefully removed the bottom of it to let out her companion, Oliver Reed!
Di and Oliver are starring in a new Relph-Dearden production for Paramount called The Assassination Bureau It's about a group of highly professional international killers with Di playing a young reporter determined to expose them.
As she stepped from the gondola, she brushed herself down and settled herself into her canvas chair to await the next take on the set at Pinewood Studios, I asked what had made her choose this role out of the many offers she has had since becoming an international star on TV in "The Avengers".
"Filming is a new medium for me," she said. "I'm rather nervous of it and I thought a comedy would be the best way of playing myself in. With comedy you know where you are. You are playing for a laugh so the aim is well defined. With a dramatic role, it is not so straightforward. The role is more a matter of personal interpretation and it is often not easy to know whether your idea is right or wrong."
The Assassination Bureau is, in fact, her second film. But she looks upon her first, which is the film version of "A Midsummer Night's Dream," as an extension of her stage career.
"I'm enjoying making The Assassination Bureau more than I thought I would," she said. "While it is a comedy, it is a comedy with a difference - slightly black in places. It's great fun and the people I am working with - Oliver Reed, Telly Savalas and Curt Jurgens - are fun, too."
She's also enjoying the Edwardian costumes and the extravagent sets. Clothes mean a lot to her. When she had finished her two-year course at the Royal Academy of Dramatic Art, she had difficulty getting started in the theatre because of her height and spent four months working as a fashion model.
That's why she was able to wear clothes with such flair in "The Avengers" and is now in this film.
Her personality is an intriguing mixture of restlessness and reserve. She was doing very well with the Royal Shakespeare Company when she took the role of Emma Peel in "The Avengers" to extend her range and to bring her to the notice of theatrical producers. The last thing she anticipated - or wanted - was to become a TV sex-symbol.
Recalled Di: "I took the role of Emma Peel because I wanted to prove to myself that I could do it after years in the classical theatre. I didn't - and still don't - want to be typed in any one kind of part or tied to one entertainment medium."
That's the reason she threw up Emma Peel at the height of her success and is now learning a new medium - films.
But she laughs off the suggestion that she might become a top film star.
"I'd like to be successful in films to satisfy my artistic ambitions - but I couldn't take all the things that go with being a film star. I value my private life too much," she says.
This is where the reserved side of her character comes in. Yorkshire by birth and Shakespearean actress by training, she seems somewhat out of place amid the back-slapping bonhomie of the film set.
She looks upon what others might think of as the rewards of being a celebrity as penalties she has to endure for the sake of her artistic satisfaction.
She finds interviews such as we were doing difficult, hates being approached in the street by strangers - particularly if they call her Emma - makes as few public appearances as possible, dodges autograph hunters and leaves the answering of her fan mail to others.
"I just don't want to get involved in that side of the business," she said. "All I want to do is act. It used to frighten me when I was doing 'The Avengers' to think that people used the image I presented on the screen to identify with some fantasy of their own. It appeared from my fan mail that thousands of people believed that Emma Peel was a real person.
"I am grateful to 'The Avengers' because it extended my range enormously and gave me financial security. But I wouldn't like to do a long-running TV series like that again. It makes me feel caged and I feel as if I have been completely taken over by it."
Although impressing everyone on the set of The Assassination Bureau with her professionalism, she is really a theatre actress by temperament. She prefers the quiet study of a long rehearsal period, with its opportunities to develop a character in depth.
She says she is at her best in the evening and hates early morning calls to a film or TV studio.
Her future? She hopes to divide her working life between her first love, theatre, and feature films, where the period of pressure is limited.
Of her private life, she will say very little except to reveal that she likes wearing trouser-suits and short, simple dresses. Hates synthetic foods, preferring to suck oranges during the day and cook herself a meal with fresh and hand-prepared ingredients at night. That she likes books, mostly serious literature, biographies and contemporary novels. That she hates jewellery. That she likes dancing, gambling and parties. Questions about romance she loathes.
"Yes, there is a man in my life - but I'm not saying who he is," is the most she will say.
Miss Rigg was anxious to get back to her movie role, so I bade farewell and wished her every success in the medium which she had openly confessed made her feel nervous. But watching her work, she didn't look as though anything really worried her.