Prankster Johnson Wen, who goes by Pyjama Man online, later identified himself on social media as the offender.
“I’m free after being arrested”, he said in an Instagram story.
The influencer has made a name for himself online with similar incidents, including accosting Katy Perry and The Weeknd at concerts.
He also gained notoriety for pitch invasions at the 2023 Fifa Women’s World Cup and Cricket World Cup finals.
His post about his stunt in Singapore today attracted condemnation from many commenters.
“You literally assaulted her. This isn’t a flex, it’s a crime. Shame on you!” one said.
Other comments echoed that sentiment, labelling his actions as “sad”, “unlawful” and “disgusting”.
Grande and Erivo star as Glinda and Elphaba Thropp (Wicked Witch) in Wicked: For Good, the conclusion of the two-part story.
The film comes to New Zealand cinemas next Thursday.
The pair’s friendship has been well documented, with both publicly sharing praise for each other.
Speaking to the New York Times last year about her relationship with Erivo during the filming of Wicked, Grande said: “That was one of my most cherished parts of this experience: I felt held and like I had a friend every step of the way.
“I’m really proud of us for how genuinely we took care of each other throughout this whole time.”