Demonstrating unusual truth in advertising, this engaging if somewhat tawdry biopic about Princess Margaret opens with the disclaimer, "Some of the following is based on fact. And some isn't." Wherever the truth lies, "The Queen's Sister" takes a lusty three-decade journey through the life of England's original paparazzi-plagued princess that's occasional fun, if probably more entertaining for those who can sing all the lyrics to "God Save the Queen."

Demonstrating unusual truth in advertising, this engaging if somewhat tawdry biopic about Princess Margaret opens with the disclaimer, “Some of the following is based on fact. And some isn’t.” Wherever the truth lies, “The Queen’s Sister” takes a lusty three-decade journey through the life of England’s original paparazzi-plagued princess that’s occasional fun, if probably more entertaining for those who can sing all the lyrics to “God Save the Queen.” Lucy Cohu (“Gosford Park”) does deliver a regal, rollicking performance in the title role, though overall this twisted “Sister” proves a little too cheeky for its own good.

Margaret is living a carefree existence in postwar Britain of the early 1950s when her father dies, putting Margaret’s sister Elizabeth (who is never shown) on the throne while dropping her further down the line of succession.

A buoyant personality, Margaret becomes enamored with a divorced war hero, but the family intervenes because such a marriage would be deemed scandalous. It turns out to be a preview of coming attractions.

Dubbed “the people’s princess,” Margaret weds a photographer, Anthony Armstrong-Jones (Toby Stephens), leading to the first televised royal wedding. Her new husband, alas, struggles under the yoke of the spotlight, and both stray outside the marriage prior to a more dubious first — a divorce in the royal household.

Director Simon Cellan Jones and writer Craig Warner provide several knowing little touches about the obsession with fame and celebrity, such as women frantically lighting up cigarettes when they espy Margaret smoking in public. There is also something poignant about Margaret chafing against the increasingly aggressive tabloid press given the fate that would later befall Princess Diana.

Still, the movie also indulges in some questionable devices, offering little glimpses of common folk to capture the disparate views of the royals as well as satiric asides from a critic who wishes to rein in their profligate spending. In addition, scenes depicting Margaret having sex, using drugs and in the nude seem purposefully provocative, though welcome nonetheless.

Saddled with heavy latex near the conclusion (Margaret died in 2002, at the age of 71), Cohu makes it all worth watching, conveying the contradictions — she can be down to earth and snotty all at once — that surely helped render Margaret an object of fascination in her time. Yet even with its sumptuous production values as Margaret jet-sets her way across the globe, it’s a lightweight confection, especially when held up against the BBC’s tony track record with historical fare.

In other words, some BBC America productions are really outstanding, and some of them aren’t.

The Queen's Sister

BBC America, Sun. March 5, 8 P.M.

Production

Filmed in London and the South of France by Touchpaper Television. Executive producer, Rob Pursey; producer, Kath Mattock; line producer, Sue Calverley; director, Simon Cellan Jones; writer, Craig Warner.

Crew

Camera, David Katznelson; editor, Tania Reddin; music, John Altman; production designer, Michael Pickwoad; casting, Jill Trevellick. 120 MIN.

Cast

Princess Margaret - Lucy Cohu Tony Armstrong-Jones - Toby Stephens Prince Philip - David Threlfall Sharman Douglas - Meredith MacNeil
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