The Queen was left "totally engrossed" by a Hollywood production company's 3D recreation of a Victorian ball – but quipped she was glad the style of dancing had died out.
The projection of eight life-size dancers in period costume is the highlight of a new Buckingham Palace exhibition the Queen and Duke of York were given a preview of ahead of its public opening on Saturday.
Visitors will be able to imagine the ballroom as Victoria and husband Prince Albert would have known it as projections on the walls and ceiling recreate the original colour scheme featuring vivid reds, blues and greens.
When the Queen first walked into the space, now used for state banquets and investitures, she glanced at the walls and quipped "look how busy it is".
Royal Collection curators turned to special effects firm Practical Magic in LA to recreate the illusion of the first ball held in the palace's ballroom in the 1850s.
The Queen spent around five minutes watching the virtual dancers who performed a quadrille, a fashionable dance in the 19th century that features four couples, to the sounds of La Traviata.
At the end, she joked: "Thank God, we don't have to do that anymore," and as she left the ballroom said "it's deceptive".
Dr Amanda Foreman, curator of the exhibition Queen Victoria's Palace, said: "She loved it, she was totally engrossed."
The historian added: "She asked me 'what am I seeing here' and I said she was seeing the first quadrille that was danced at the first ball when the ballroom was opened in 1856 and that these figures, who are all historically accurate, we've had them tell a story.
"So there's one couple who fall in love over the course of the two and a half minutes of dancing, there's a woman and it's her very first time at a ball so she's learning – so I told her that story and she stayed to watch it."
Practical Magic used a technique popular in Victorian theatres known as Pepper's Ghost, where an image is projected onto a tilted piece of glass giving the illusion of a someone being in a room when they are not.
Matthew Lewis, president of Practical Magic, said he told the Queen the apocryphal story of how the illusion was finally revealed to an audience – someone threw a drink at the glass.
He added: "When I told that to the Queen she got a laugh out of it, the Queen felt that was a funny story."