The Queen joined passengers on a train from London to Norfolk for the start of the Royal Family's traditional Christmas break on her Sandringham Estate.
The Queen got off the train from King's Cross at King's Lynn station and walked up the platform with her security staff and the Duke of Edinburgh as commuters looked on.
Travelling on the 10.44am train out of King's Cross station in London on Thursday, the royal couple arrived at platform one in King's Lynn at 12.24pm - three minutes late.
Fellow travellers were unaware she was on board until they exited the train to be greeted by a large police and media presence.
One said: "What's all the fuss about - are you expecting somebody?"
It is understood the Queen paid for a standard ticket costing £34.40.
Wearing an overcoat and headscarf to guard against the cold, she mingled with passengers on the platform before being escorted to a waiting Range Rover.
The Duke of Edinburgh, who in recent years has travelled separately, escorted her.
The couple travelled by car to the Sandringham Estate, close to the Duke and Duchess of Cambridge's Anmer Hall home, and will be joined by the rest of the family for Christmas Day.
Most of the family are expected to attend a Christmas Day church service on the estate where hundreds of well-wishers will watch on.