Helen Mirren Nintendo Wii balance board

Helen Mirren shows off her Nintendo Wii balance board skills. Photos courtesy of Nintendo

Helen Mirren may have recently played coy about maintaining her enviable bikini body (stripper heels and sucking it in? hmmm), but we think we've finally unearthed the 65-year-old siren's fitness secret: Nintendo Wii.

The Oscar-winning actress -- who recently went topless for New York Magazine -- has just been tapped to promote Wii Fit Plus in the company's UK holiday campaign, according to a press release.

Take that, Jane Fonda!

Glad in chic workout wear -- slim drawstring pants and wraparound tops -- the inspirational "gramazon" breaks a sweat as she exercises using the interactive fitness system. Hot dame!

"This year's star line-up is the best yet, demonstrating the wide appeal of Nintendo products," Nintendo UK marketing director Dawn Paine says in the release.

"This Christmas, with the help of our celebrity friends, we will be helping the nation play together and have fun whatever their age."

Sadly, the ads won't be hitting U.S. TV screens, but that doesn't mean we can't bust a move Mirren-style. Sixty-something six-pack, here we come!

Meanwhile, check out how Mirren's style has evolved over the years.