Helen Mirren, who swept Hollywood’s awards season last year with her work in The Queen, is trading in her tiara for bumps and bruises.

The 62-year-old actress did her own stunts for the big-budget action flick National Treasure: Book of Secrets, her first film since winning an Academy Award.

She didn’t take on the role to add to her arsenal of awards. She took it to have some fun.

Ever regal with her platinum pixie haircut and black skirt suit, Mirren talks about her future as an action hero and life after Oscar.

Why do National Treasure?

[Laughing] Why do something as fun as this, why do something as exciting as this, why on Earth do something as popular as this, why do something as well-budgeted as this? Is she insane?

Is she?

No, she’s really, really sensible. She knew what she needed to do. I’m not talking about career move, I’m just talking about my personal pleasure, my personal fun. … I wanted to be in a sort of ensemble piece, I didn’t want to be the star of the piece, and I’ve never been in a big, big, big-budget movie before. It was wonderful to participate in something like that where there is enough money to do what you want to do.

You had these expectations of what comes with being in a Jerry Bruckheimer movie, and yet acting is acting, isn’t it?

Acting is acting, but acting is different in almost always every project, and very, very different in this context. … You look at that lineup: Ed Harris, Harvey Keitel, Jon Voight, myself, Nicolas Cage, Diane Kruger and Justin Bartha. You know, pretty bloody impressive, but it needed all of our expertise and our professionalism to really make the characters pop, make the characters work. I hope if the film works, it works on that level as well as all the wonderful effects, the grandeur of it, the adventure of it. But you can have all the adventure of the world without characters that spark, it becomes boring.

You did your own stunts?

I guess, yes, I did. Certainly the swinging on the wire, the swinging on the vine I did, and everything in the water I did, yes, of course.

How was it?

Well, it was the best thing of my life! [Laughing] It was fantastic, at the end of swinging on the vine they just, the whole crew just thought I was so funny because I was just yelling with pleasure. I was so excited about it. And I said to [director] Jon Turteltaub at the end of the day that that was the best day of my professional life.

So now, Oscar winner, and action hero?

[Laughing] Yes! Yes, absolutely, I hope so. I would be so thrilled of people seeing me as an action hero. That would be a pinnacle of my career definitely.

Helen Mirren refuses to let the glare of the best actress Oscar trophy distract her from opportunities for fun. So soon after scooping up the statue for her Elizabeth II portrayal in The Queen, she was ready to co-star in the Nicolas Cage action picture National Treasure: Book of Secrets. “It’s good fun,” says Mirren. “And I thought, why not try something I’ve never done before?”

In the sequel, which opened in late December, the 62-year-old portrays Cage’s mother, a linguistics expert who joins a quest to find a book of centuries-old government secrets in order to clear the family’s name.

Besides firing off some snappy dialogue, Dame Commander of the Order of the British Empire managed to run and jump — and even swing on a rope. “It was different for me, but I appreciate the challenges of these kinds of films much more than I used to,” she says.

Certainly, Cage is even more of a Mirren fan than he was before filming started. “She is really down to Earth, and doesn’t take herself too seriously,” he says. “And I have to tip my hat to her that she would win the Oscar, then go on to make an adventure film. That shows a lot of spirit and a great zest for life.”

When Mirren is told of the Cage compliment, she is pleased. “I’ve always considered myself a working actor, so I am very happy he feels that way,” says the actress, who has also been Oscar nominated for 1994′s The Madness of King George and 2000′s Gosford Park.

Next up for Mirren is another big studio movie, this time with Russell Crowe. “I am scheduled to begin State of Play by mid-January,” she says of the crime thriller.

In March, she is slated to star in Love Ranch, directed by her husband, Taylor Hackford. She plays a madame who runs the first legal brothel in Nevada. “Now that should be something we can all have fun with,” says Mirren, chuckling.