Prince Edward blended into the crowds as he caught a train on the London Underground.
The Earl of Wessex, 58, was spotted on the Jubilee Line on Monday after spending the day celebrating winners of the Duke of Edinburgh’s Gold award.
As other commuters concentrated on their journeys, the Queen’s third child seemed to be in conversation with another man holding a similar umbrella.
He was seen getting on at Green Park and departed at Waterloo.
A spokesman for the Royal Family confirmed the Earl- who is ninth in the line of succession to the throne- was on the underground.
He added: “It’s not uncommon for him to catch the tube.”
The prince’s less than glamorous journey comes amid Britain's worsening cost of living crisis - and just a week after a crown was chauffeur driven to Parliament for the Queen’s Speech.
Traditions dictate the priceless headwear is driven in a carriage ahead of the monarch, who missed last week’s opening of parliament for the first time in 59 years due to ill health.
Prince Charles stepped in to read her speech for the first time, accompanied by Prince William who had never attended before.
The prince was back on the underground earlier today when he was joined by the Queen to officially open the new Elizabeth Line at Paddington Station.
The Earl was due to mark the completion of the line named in honour of Her Majesty, but at the last minute the monarch decided to attend as well.
On arrival the Queen was welcomed by the Prime Minister, the Mayor of London, the Secretary of State for Transport and the Commissioner for Transport for London.
She also unveiled a plaque to mark the line’s official opening.
Using a walking stick, she smiled warmly as she met Crossrail and Elizabeth line workers.
She also had a new experience as workers gave her an Oyster travel card and showed her how to use the ticket machine.
The Queen proceeded through the ticket barriers down to the Elizabeth Line platform to hear about the design of the new stations and trains.
A Buckingham Palace spokeswoman said: "In a happy development, Her Majesty The Queen is attending today's event to mark the completion of the Elizabeth line.
“Her Majesty was aware of the engagement and the organisers were informed of the possibility she may attend."
The nation's longest reigning head of state is just over two weeks away from her Platinum Jubilee celebratory weekend.
The £18 billion rail project was originally due to be opened in December 2018, but had been repeatedly delayed by issues with safety testing and signalling systems, even before the onset of the pandemic.
Originally named 'Crossrail', the Elizabeth line will connect destinations west of London, including Heathrow airport and Reading with Shenfield in the east.
Doors to the new line will open to passengers on May 24.
