Zayn Malik and Louis Tomlinson have been caught on camera joking about drugs and seemingly smoking a marijuana cigarette.
The stars make up two fifths of British boyband One Direction, who are known for having hordes of teenage fans.
The group are currently on their Where We Are Tour, which saw them visit Peru on April 27. In a video posted on MailOnline, Louis and Zayn are seen inside a vehicle on the day they performed at the Estadio Nacional in Lima.
"So here we are, leaving Peru. Joint lit. Happy days!" Louis is heard saying behind the camera.
The journey takes 15 minutes and there are three other people in the car, although they are not the other members of the band – Harry Styles, Liam Payne and Niall Horan – who are thought to have travelled separately.
As the camera begins rolling, Louis appears to realise what some of the other people in the car are talking about.
"It's about the joint. What a great thing to capture in a different language. They were just asking if it's OK," he says.
One of the other men asks: "Are we allowed to talk contraband in this?"
To which Louis quickly replies: "Yes, that's what it is about."
Louis is then heard saying he wants to "light up" as the car drives out of a parking lot, with a rolled cigarette appearing to be lit on camera. He is then heard joking about a police bike which is escorting the vehicle, becoming more excitable as time goes on.
"One nil b***h! Look at this b***h! He's having a look. He's thinking, 'I'm sure I can smell an illegal substance in there.' And he's hit the nail on the head," he says.
During one point Louis turns his attention to Zayn, who is sitting beside him. He appears to claim that Zayn smokes marijuana, with Zayn seemingly accepting a joint which is offered to him and then inhaling.
"Zayn takes his job very seriously. He makes sure he goes through a two hour intense warm-up before every show.
Just to get himself in the zone for the show," Louis says as Zayn jokingly sings in the background.
"One very, very important factor of Zayn's warm up of course if Mary J herself. In fact I will present it to him now for some fantastic singing."
Later the boys start discussing "culture" as the camera hones in on their cigarette, with Zayn saying he is really excited about the "culture when we get to Jamaica".
The group also refers to "chicken" throughout the clip, although exactly what they mean is unknown.
Zayn and Louis also discuss One Direction merchandise during the journey, with Zayn claiming their last book was "not cool" and that they should try to emulate a tome by Kid Rock.
In Peru, marijuana possession isn't punishable as long as it is for personal use and is less than eight grams.