The political correspondent has a contract to give after-dinner speeches and show off his dance skills on a cruise that includes a trip through the Panama Canal.
The trip begins six days after his last appearance on the BBC1 talent show, on Saturday night, and has prompted speculation he quit because he had expected to be voted out by viewers before the holiday started.
Sergeant, 64, has denied there is any connection between the trip and his decision to leave the programme, whose final episode will be broadcast on the Saturday before Christmas.
"I do have a contract with a cruise liner to take me through the Panama Canal in a couple of weeks, but that didn't have anything to do with it," he insisted.
He will appear on the P&O vessel Oceana, which is scheduled to visit nine countries in 14 days. A spokesman for P&O said: "No doubt John will give some tango tips."
Somehow, I think he weighed it all up and decided to go for the bigger money....
Funny about the timing though........