Queen Elizabeth has a reputation for being a bit … staid … but the 94-year-old is quite different behind the scenes, according to her biographer Sally Bedell Smith, author of Elizabeth the Queen: The Life of a Modern Monarch.

Smith tells People she spoke to an insider at her estate in Norfolk, Sandringham, who said: ” 'You can hear her laugh throughout that big house.' She has a big laugh!”

While watching a rerun of Prince Charles‘ 1981 wedding to Princess Diana, she said: “'Oh, there's my Miss Piggy face.’ She has the ability to laugh at herself.”

Smith told People that during a shoot celebrating her Diamond Jubilee in 2012, she told photographer Barry Jeffrey to “just keep the camera rolling!” as she broke from the norm.

The Queen proceeded to strike a “series of poses, slipping her hands in and out of her pockets and placing them onto her hips, mimicking the stances of a professional model,” her dress maker and close confidante Angela Kelly told Smith.

They stood “in disbelief. The Queen was a natural,” Kelly marveled. “Barry and I felt we were experiencing something really special: a moment never to be repeated.”