Ariana Grande cheers on Broadway beau Ethan Slater during ‘Spamalot’ show

Ariana Grande is her Broadway boyfriend Ethan Slater’s biggest fan.

On Tuesday, the God is a Woman songstress was front and center for the first preview performance of Broadway’s Spamalot revival at the St. James Theatre in New York City, cheering on her boyfriend who plays The Historian/ Prince Herbert.

An Instagram video uploaded by attendee Jim Glaub showed the Grammy-winning musician giving a standing ovation with the rest of the audience as colourful confetti rained down on them.

A source told People Magazine that Grande, a theatre kid herself, has been a “big supporter” of the production and “already has plans to go again.”

“She was so sweet last night, taking pictures with fans and gushing about how much she was enjoying the performances,” the source praised Grande. “She’s a theatre kid at her core, so you see she really feels at peace being around Broadway.”

The Side to Side singer was accompanied by her brother Frankie Grande and best friend Doug Middlebrook, the latter of whom she was later snapped leaving the venue with.

During the event, the pop star also snapped a selfie with Victorious co-star and long-time friend Liz Gillies.

Grande, 30, and Slater, 31, met on the set of the upcoming music adaptation of Wicked, and confirmed their relationship in July after the former separated from husband Dalton Gomez and the latter divorce from wife Lilly Jay.