“Ariana is serious with Ethan,” they said. “She loves being with him.”

The insider added that while the pair “go out occasionally” as Grande puts the finishing touches on her upcoming album, they “mostly enjoy staying in. It’s a very normal relationship.”

Ariana Grande and Ethan Slater Step Out Together for Dinner with Her Dad: ‘They Love to Support Each Other’ Says Source

Last Friday, the couple was pictured together for one of their first times out together.

The singer and Broadway star were photographed during a night out in New York City when a source close to Grande told PEOPLE they ate dinner with her father Ed Butera at her family’s favorite Italian restaurant before seeing Slater in Spamalot.

Grande sported an all-black with a furry bucket hat, mini skirt, and black top with furry cuffs. Meanwhile, Slater opted for a more athletic getup with a zip-up, joggers and running shoes.

“They love to support each other in their work,” the source said. “When she’s done with work, Ariana loves going to the theater when she can.”

Grande shared a carousel of photos to Instagram earlier this month, which featured one image with a Spam can ornament hanging on a wall Christmas tree made of green garland.

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The ornament is, of course, a shoutout to Spamalot, the 2005 Tony-winning musical adaptation of Monty Python and The Holy Grail. Slater is currently starring in a revival of the comedy on Broadway.

Grande has has visibly supported her beau multiple times at the St. James Theatre in New York City since it began rehearsals in October. She was seen cheering him on during the show’s first preview performance on Halloween and attended the opening night of the Broadway musical on Nov. 15.

The couple initially met on the set of the upcoming movie adaptation of Wicked and developed a romance offscreen.

Grande and Slater’s relationship was first confirmed by PEOPLE in July and started after her separation from husband Dalton Gomez and Slater’s separation from wife Lilly Jay. Grande and Gomez, 28, settled their divorce in October after two years of marriage.