After premiering on July 1, Minions: The Rise of Gru raked in $125 million in domestic ticket sales over its four-day opening weekend. The film brought in an additional $93.7 million from international markets.

There are certainly people who were committed to seeing the latest installment of the highest-grossing animated film franchise of all time. But the movie’s success is also due to a viral TikTok trend, in which groups of mostly young men put on formalwear to watch the latest movie, and then share videos of their escapades on the social media platform under the #gentleminions hashtag. Nearly 90% of The Rise of Gru’s audience has been 25 or under so far, with 25% of attendees younger than 12 years old, according to The Hollywood Reporter.

So how did this all start? 

A week ago, Bill Hirst, an Australian teen, made one of the first renditions of the so-called #gentleminions trend in a TikTok video that has now received over 35 million views. The Rise of Gru was released in Australian theaters on June 23, a week earlier than in the U.S. 

To the sound of California rapper Yeat’s song “Rich Minion”—featured in the new film—Hirst posted clips of himself and his friends wearing dark suits and ties, going single file up an escalator, and mimicking the character Gru’s hand motions during the movie.

Hirst told Fortune his friend got the idea during the week before the Rise of Gru’s release, from memes joking about showing up to the Minions movie in formal attire. That’s when Hirst and 15 of his friends decided to make it a reality. 

“Alongside our love for the previous films and them being a nostalgic part of our childhood, we couldn’t resist such a humorous and rare occasion to take part in with our mates, whilst also thoroughly enjoying the new film and overall the experience,” he told Fortune.

At the theater, Hirst saw two other separate, smaller groups wearing suits and dressing up as Minions.  

Since he posted it last week, Hirst’s TikTok has gone viral and even inspired a response from the movie’s official @minions account. 

On July 1, the U.S. release date for the film, the @minions TikTok account overlaid a yellow Minion cartoon and the words “Your day has come” over Hirst’s video playing in the background. “Bobspeed you gentleminions,” the account wrote in its caption, adding a suit emoji. 

Universal Pictures, which distributed the film, also endorsed the trend on July 1, tweeting, “to everyone showing up to @Minions in suits: we see you and we love you.” 

When social media personality MrBeast took on the trend, he rented out an entire theater. MrBeast, who has over 98 million subscribers on YouTube, was not the only celebrity to re-create Hirst’s video and receive millions of views. Wearing his own suit and tie, Broadway actor Kevin Chamberlin, known for playing Uncle Fester in The Addams Family, also filmed himself making “Gru” hand gestures at the theater for TikTok. 

Not so gentleminion-ly?

While creating the video, Hirst said he received an overwhelmingly positive response from staff and other patrons at the theater.

“Fortunately due to it being most likely the first time the employees and other onlookers had seen people in suits at the cinemas, everyone got a good laugh out of it,” he said. “And with no disturbance during the film, only applauding at the beginning and end. The whole crowd had a great time.”

But not everyone taking part in the trend has been welcomed by movie theaters. 

Theaters have called out suit-clad groups for being incredibly disruptive, and some even started banning them from viewings. 

Clips on TikTok show some besuited moviegoers shouting at the screen, throwing bananas, and loudly making Minion sounds. Theater staff took to Twitter to share the large messes left behind by the gentleminions and their antics.  

A sign from Odeon Cinemas was reposted multiple times on social media, noting that “any groups of guests in formal attire will be refused entry for showings of Minions: The Rise of Gru.” A spokesperson from Odeon Cinemas confirmed to Fortune that “due to a small number of incidents in our cinemas over the weekend we have had to restrict access in some circumstances.”

Universal Pictures did not respond to Fortune’s request for comment about the bans.