Ariana Grande cheers on beau Ethan Slater's big career move

Ariana Grande made sure she was supporting Ethan Slater during his major milestone.

On Tuesday, the 30-year-old singer was seen among the 60 people in the audience of her Wicked costar-turned-boyfriend Ethan Slater's opening night performance of his debut residency at Café Carlyle in Manhattan's Upper East Side.

According to The US Sun, Ariana remained unnoticed throughout the night while wearing a plunging red puff-sleeve dress in the back booth “until the lights went back on.”

“Everyone got up to either leave or wait to say hi to Ethan, who was mingling with guests after,” an eyewitness told the outlet.

They added, “Ariana and Ethan did not interact after the show was over because he was greeting his fans and it was obvious she did not want to steal the spotlight from him. She was just there to support him.”

Another insider told PEOPLE, “She was laughing at all of his jokes in between songs, and cheering for him after each song. The show was mostly about him and his love of music and theater, though he did steal a quick glance over to Ariana when he sang a line about being ‘lucky to be in love.’ It was very cute.”