Damon recalled how shooting for the scene became an unforgettable experience as he caught a whiff of his costar's onion breath.

The incident reportedly happened when they were shooting their 2011 movie "We Bought a Zoo".

"What happened was, we did a shot before lunch, and it was this nice little two-shot that ended in the kiss," Damon told Emily Blunt during a LADbible TV interview as quoted by Pop Sugar.

"And it was really good. And we went to lunch, and she and I both thought it was over, but it wasn't," the actor said.

Damon said the director had asked them to film more close-up scenes after they returned from lunch.

"She came in and Cameron Crowe had set the camera up and it was a tight shot of the kiss," Damon said.

"And she goes, 'Oh sh*t! I literally just had an onion sandwich!'"Matt Damon recollected.

Matt said he kept making fun of her about the situation ever since the incident happened.

"I was making fun of her the entire time about her onion breath, which I didn't even smell," he said.

Matt Damon's latest movie Oppenheimer was released last week.

The movie is making a strong performance at the global box office.

We Bought a Zoo is a 2011 American biographical family comedy-drama film loosely based on the 2008 memoir of the same name by Benjamin Mee.

It was co-written and directed by Cameron Crowe and stars Matt Damon as widowed father Benjamin Mee, who purchases a dilapidated zoo with his family and takes on the challenge of preparing the zoo for its reopening to the public.

The film also stars Scarlett Johansson, Maggie Elizabeth Jones, Thomas Haden Church, Patrick Fugit, Elle Fanning, Colin Ford, and John Michael Higgins.