Queen Elizabeth 88th birthday

Queen Elizabeth II is looking great at 88 in this portrait commissioned on behalf of the British Government's GREAT Britain campaign. (David Bailey/AP)

A portrait of Queen Elizabeth by renowned British photographer David Bailey was unveiled today to mark the monarch's 88th birthday.

The black-and-white photograph, taken at Buckingham Palace in March, was released on Twitter, too.

It shows the queen smiling broadly, and captures the "granny" aspect of her often impassive-in-public personna. Bailey described his subject as a "very strong woman" with "very kind eyes with a mischievous glint."

She is pictured wearing pearls, and a dress by Angela Kelly, her personal assistant and senior dresser to her since 2002, according to the BBC. The queen sent Kelly to help granddaughter-in-law Duchess Kate of Cambridge prepare her wardrobe for her three-week tour of Down Under, which has been a huge success so far with one week to go.

The queen's portrait, unveiled today for the queen's birthday on Monday, was commissioned for a government campaign to promote Britain's heritage and tourism to potential visitors abroad.

Britain's monarchy and royal history is one of the biggest drivers of its strong tourism industry.

The queen has been painted or photographed many times, especially around the Diamond Jubilee in 2012 when she celebrated 60 years on her throne.

Her birthday is celebrated twice a year: Her actual one on Apr. 21 is celebrated privately, while a public ceremony in June (when the weather is usually better) marks the occasion with a Trooping the Colour parade in London that is a favourite of the tourists.

Bailey, 76, who grew up in London's East End and made his name working for Vogue magazine in the 1960s, is celebrated for his portrait photography of such stars as Jack Nicholson, Sir Michael Caine and Johnny Depp.

He said he's always been a fan of the queen. "I've always liked strong women, and she is a very strong woman."