Amir Khan claimed to have been robbed at gunpoint in Leyton, east London on Monday.
The 35-year-old former unified light-welterweight world champion, who won a silver medal at the 2004 Olympics, detailed the incident in a tweet.
Khan said he was with his wife Faryal Makhdoom when they were approached by two men who demanded his watch. He noted that both he and his wife were unharmed.
"Just had my watch taken off me at gunpoint in east London, Leyton," Khan's tweet read.
"I crossed the road with Faryal, luckily she was [a] few steps behind me. [Two] men ran to me, he asked for my watch whilst having a gun pointed in my face. The main thing is we're both safe."
Khan returned to boxing after a long hiatus in February for a clash against rival Kell Brook, losing via sixth-round knockout in Manchester.