Television presenter Aled Jones was robbed of his Rolex Daytona by a teenager wielding a machete.
Mr Jones’ son Lucas, 18, witnessed the broad daylight theft.
The couple were walking through Chiswick, West London, when targeted.
The 52-year-old Songs of Praise host was left “shaken” after handing over the £17,000 watch.
He called the police and a youth aged 16 was arrested soon afterwards.
The theft was reported in The Sun.
A source told the newspaper:
“Aled was totally shocked as it came out of nowhere and it all happened so fast
“The robber threatened him with the machete and demanded the Rolex.
Luckily Aled was savvy enough not to put up fight for the watch while he was having a deadly weapon waved at him.
“The attacker had seen the Rolex and targeted him specifically – although Aled was shaken afterwards, he was quite relieved.
He was glad he and Lucas were not hurt and that they got home safely to the rest of their family.”
People seen out and about wearing high-end watches are often targeted by thieves.
Security expert Christopher Marinello, founder of Art Recovery International, told the Times:
“Gangs are looking at them and thinking, ‘He’s staying at this hotel in London and he’s got these Hublot watches.
“Let’s wait for him to pop out and we’ll get him.
“You can’t blame people for wanting to show off what they have but there simply aren’t enough police on the street these days.
“You can’t go out to dinner in Mayfair wearing a high-end watch.
“These robberies happen several times a week and thieves are becoming more violent.”