Shoppers were amused after a man stepped out in central London on Friday wearing only a mask.
Some pedestrians stopped in their tracks to take photos of the man while others gaped in shock.
It was unclear what prompted the stunt but his walk was captured by a Reuters photographer from an office above the street.
People buying a takeaway coffee are among those required by law to wear a face-covering.
However, some high street chains have said they will not penalise customers who fail to do so.
Police can hand out £100 fines to people in shops, shopping centres, banks, takeaway outlets, post offices, sandwich shops and supermarkets who flout the rules.
However, the College of Policing has said officers “should only be required as a last resort”.