Actor Christopher Plummer. (Zack Seckler/Getty Images)

When interviewing Christopher Plummer, there is always an elephant in the room — a singing elephant, to be exact. You don’t want to mention it; you know that he’s referred to it disparagingly in the past as “The Sound of Mucus” and “S&M.” But readers are curious. After all, despite a vast and varied resume onstage and in film, Plummer’s most beloved role remains Capt. von Trapp in the treacly 1965 movie of The Sound of Music.

" When you get to my exalted age, you have to work. The more you work, the younger you appear to be, I think, and the younger you feel.”—Christopher Plummer

Midway through our recent talk at the Stratford Shakespeare Festival, I broached the subject. No sooner is the title out of my mouth, than Plummer quickly nods, ready to set the record straight. Whatever he may have said about the picture itself, he has fond recollections of the people involved with it.

“I made a great lifelong friendship with Julie [Andrews], whom I adore,” he says. “And I loved the director, [the late] Robert Wise; I spoke at his memorial in Los Angeles. I have terrific memories of making it.” But he doesn’t think much of Andrew Lloyd Webber’s forthcoming revival of the musical in Toronto, or the way its star was chosen via the CBC-TV series How Do You Solve a Problem Like Maria? “At one point, Julie and I were approached to do the reality show,” Plummer says, laughing incredulously. “No, thank you!”

Plummer discusses the film, along with many other highlights in his remarkable 60-year career, in his memoir, In Spite of Myself, to be published in Canada this fall. It’s a career that is still in full swing. At 78, the great Canadian actor is headlining at Stratford once again, in an eagerly awaited production of George Bernard Shaw’s Caesar and Cleopatra that began previews Aug. 7. He came straight to the festival from Berlin, where he was shooting The Last Station, a film about Tolstoy, with Helen Mirren and Atonement’s James McAvoy. Before that, he wrapped up his title performance in Terry Gilliam’s forthcoming fantasy, The Imaginarium of Dr. Parnassus, co-starring with the late Heath Ledger.

Plummer, left, and Nikki M. James star in Des McAnuff's production of Caesar and Cleopatra. (Stratford Shakespeare Festival)

That’s typical of Plummer’s whirlwind schedule in recent years, which has seen him appear in a succession of high-profile films while still taking on major stage roles – like the Clarence Darrow figure in last year’s Broadway revival of Inherit the Wind, which garnered him rave notices and a Tony nomination.

“I haven’t stopped working for the last six years,” Plummer admits. “It’s been bang-bang-bang, one thing after another.” The heavy workload is entirely intentional. “You know, when you get to my exalted age, you have to work,” he says with a smile. “The more you work, the younger you appear to be, I think, and the younger you feel.”

Plummer does look youthful for a man near the end of his eighth decade. His grey hair is thinning, but his eyes are still a penetrating blue, and he retains that patrician elegance that has served him well in roles ranging from the Duke of Wellington to King Lear. Dapper even in his rehearsal togs – a black tracksuit topped with a black blazer – he leans back in his chair and toys with a pair of yellow wrap-around shades. It strikes you that he has the perfect air of regal amusement to play Shaw’s Julius Caesar – a part Plummer coveted in vain for years.

“I could never get a director to be interested in this play,” he reveals. That is, until Des McAnuff, an old friend and Stratford’s new artistic director, agreed to stage it. “It’s a tremendous director’s piece, as Des is proving.” It’s also a rare opportunity for Plummer to do a Shaw work. “I think I have an ear for his rhythms,” he says, “and I particularly like Caesar because the play not only is funny, but has a great deal of romance and an attempt at historical accuracy. It’s bigger than most of his other plays. Someone once said that it was the closest thing he got to a Shakespearean play in size.”

(Knopf Canada)

But Shaw’s portrayal of the Roman general is very different from Shakespeare’s. “Julius Caesar in Shakespeare’s play is merely a figurehead,” Plummer says. “Shaw’s Caesar is huge in comparison and terribly funny, very witty. And then there are moments of great loneliness that happen to Caesar; you realize what a lonely person he must have been, because there were very few people in the world who could match him. He was so far ahead of the game and of the society surrounding him.”

Shaw’s comedy focuses on the aging Caesar’s visit to Egypt, where he takes the teenage Cleopatra under his wing and teaches her to be a queen. Plummer points out its similarity to Shaw’s later, better-known Pygmalion – the source for the musical My Fair Lady. Caesar and Cleopatra here are mentor and protégée – with a hint of an underlying May-December romance.

“There’s that hidden tease that Shaw is always giving us, that suggestion of a sexual relationship,” Plummer says, “which, of course, they really had: he fathered her child. But it’s merely suggested in the play – subtly suggested.”

Playing Cleo to Plummer’s Caesar is Nikki M. James, a protégée of director McAnuff’s and also the star of his Romeo and Juliet. “She has such fire and energy and she’s absolutely delightful,” Plummer says of the 27-year-old actress. “Never has there been a Cleopatra, in my memory, that suggested 16. She looks 16. So there’s an added sense of Caesar as a father-like tutor.”

Plummer says he’s back at Stratford – in his first starring role there since 2002’s King Lear – partly to do this play, partly to throw his support behind McAnuff’s first season as artistic head. “He’s probably the hottest director at the moment in the theatre, anywhere,” Plummer asserts. “It’s wonderful that he’s here.” Plummer jokes that he’s even pushing McAnuff to cast him in Guys and Dolls, the director’s next Broadway musical. “I keep auditioning for him all the time, just to tease him. I come in singing [he switches to the gravelly New York accent of Guys and Dolls’ Nathan Detroit] Serve a paper and sue me, sue me…”

Plummer’s challenge would be to shoehorn another stage role into a calendar already overflowing with film work. He says he’s pleased with the kinds of films he’s being offered these days – movies like Syriana, Emotional Arithmetic and Closing the Ring. “I haven’t always liked the films I’ve done,” he says. “They have been a [financial] necessity, as they often are in most actors’ lives.”

Plummer as Arthur Wellesley, the Duke of Wellington, in the classic war film Waterloo. (Mosfilm/Paramount Pictures)

He enjoyed playing a Faust-like magician in Dr. Parnassus, his first film with the visionary Terry Gilliam, which he describes as “a wonderful, fantastical piece of imagination.” It was, of course, also an experience marred by tragedy. The movie’s fate was temporarily on hold after co-star Ledger died of an overdose midway through shooting. “It was a tragic loss,” Plummer says of the young Australian actor. “He was growing and growing in power. He was a very talented boy with everything to live for.” Gilliam was able to salvage the project when three other actors agreed to fill in for Ledger. “Luckily, for the film’s sake, it’s magical,” Plummer says. “So Heath turns into Johnny Depp, Colin Farrell and Jude Law. The picture will have a curiosity value, just as indeed [The Dark Knight] did.”

As we talk movies, I have to tell Plummer that, in my household, the favourite Christopher Plummer film wasn’t The Sound of Music, but 1970’s Waterloo. My oldest son, as a little boy, watched the video of that battlefield epic over and over, and took to swaggering about the house, imitating Plummer’s supremely cool Wellington. When he hears that, Plummer erupts with a rich laugh.

“We made that in Russia and it was such a horrible shoot,” he confides. The director, Sergei Bondarchuk, had just come off the six-year filming of his mammoth War and Peace and brought along his overworked technical team from that picture. “All the special effects guys were so tired,” Plummer recalls. “They went berserk in Waterloo; they shot off explosions under my horse by mistake. The horse bolted and we ended up somewhere in Czechoslovakia! I’ve written all about it in my book.”

Plummer says his memoir has been in the works for some time – only because his acting gigs have kept him from writing it for long stretches. “I’ve tried to make it as amusing and as light as I possibly could,” he says modestly. “I hope people will enjoy it.” If it’s even half as colourful as his life, it should be quite the read.

Caesar and Cleopatra runs Aug. 7 to Nov. 9 at the Stratford Shakespeare Festival in Stratford, Ont. In Spite of Myself will be published by Knopf Canada in October.

Martin Morrow writes about the arts for CBCNews.ca.