The Queen made a moment of TV magic on Friday when she appeared behind two newsreaders while they were live on air. The monarch was taking a tour of the news channel studio at the BBC's new central London headquarters, and could be clearly seen in the background during a broadcast, to the great delight of viewers and staff.
Workers broke into a round of applause as she appeared in shot, causing newsreaders Julian Worricker and Sophie Long to turn around in surprise.
The Queen had smiled broadly as she arrived to open the revamped Broadcasting House, despite the fact that her husband Prince Philip was lying in a hospital bed less than half a mile away.
The Duke, who will celebrate his 92nd birthday on Monday in hospital, was meant to be by her side, but was admitted on Thursday evening for an exploratory operation.
Crowds had gathered to welcome the beloved royal, 87, who looked elegant in a powder blue coat and hat, and hundreds of BBC staff lined an open atrium for her arrival, with some cheering as she stepped from her chauffeur-driven limousine.
She began her tour by visiting BBC Radio 1 and meeting presenters including Nick Grimshaw, Trevor Nelson and Sara Cox. She then visited the station's famous Live Lounge to watch a performance by The Script, whose lead singer Danny O'Donoghue is a judge on The Voice.
At the end she chatted briefly with the star, and when she learned he was playing the Glastonbury Festival, joked, "Glastonbury, the place you get covered in mud?"
Danny replied with a laugh, "You've got to bring your wellies!"
The Queen also appeared live on Radio 4 to give a short address declaring the BBC's new £1billion home open.
"I remember first coming to Broadcasting House with my father, the King, and my mother and sister shortly before the war," she recalled. "I came again with the Duke of Edinburgh shortly before the coronation in 1953."
She added, "I hope this new building will serve you well for the future and I am delighted to declare it open today."
Her Majesty was introduced to a host of BBC stars during her visit, including David Dimbleby, Strictly Come Dancing trio Sir Bruce Forsyth, Tess Daly and Claudia Winkleman and newsreader Fiona Bruce.
At the end of her visit, she unveiled a plaque to mark the occasion.