The Winnipeg Centre representative voted on a procedural motion to adjourn debate, then left his seat for a moment.
When Conservative MP Royal Galipeau asked deputy speaker Joe Comartin if a vote still counts if an MP leaves while it's being counted, Martin stood up to offer his explanation.
"I can blame it on a sale that was down at the Hudson's Bay [Company] – they had men's underwear on for half price. I bought a bunch that was clearly too small for me and I find it difficult to sit for any length of time," he said.
"I apologize if it was necessary for me to leave my seat briefly, but I did not mean to forfeit my right to vote."
After a mix of cheers, applause and laughter from the benches, Comartin was forced to rule on whether Martin's vote would count.
"Let me try to deal with this with at least some seriousness, we all understand that we have to be in our seats at the time the motion is read ... the member for Winnipeg Centre was in his seat at that time. He did step out of his chair for a very short time and was directed by me to sit down again," Comartin said.
"I didn't understand the explanation at the time, that he subsequently gave … can't say I really understand it at this point."
Comartin then said that since Martin was in his seat when the vote was read and also when he voted that his vote was able to stand.