A thief stole a £15,000 watch after visiting a jewellery store posing as a customer who had come into money.
The man targeted Nathan and Co, on Church Street, Blackpool, with another man who waited outside at 4.55pm on Friday.
He said his name was Jay and he had called the week before saying he would be coming to look at expensive watches.
He tried on an 18 carat white gold Rolex Daytona, model number 116509, and ran off while still wearing it. Both men ran away up Talbot Road onto Alfred Street.
The thief was white, 6ft 1ins, muscular with tattoos and wore a dark cap, long sleeved grey T-shirt with a dark collar, blue jeans and dark trainers with white soles. The second man had a dark complexion and wore sunglasses.
Anyone with information should call 101.