Rumors about the couple's romance have been swirling for about a month, and—while they've been spotted on several low-key dates lately—the 23-year-old really confirmed things when she brought the rapper to the 2016 MTV Video Music Awards as her date.
Following her performance with Nicki Minaj, Ariana joined Miller, 24, in the audience, canoodling with him throughout the show. But it didn't just stop there! The pair brought their love fest to the Republic Records VMA after-party where the "Dangerous Woman" singer was photographed smooching her man while cuddled up on his lap.
So what does Frankie Grande have to say about his little sister's new romance?
The Big Brother star chatted with E! News' Sibley Scoles at the VMAs and revealed that the only thing that matters to him is Ariana's happiness.
"I judge my sister's happiness based on her," he told us. "She makes her own choices, and as you see she's a very dangerous woman. So nobody can tell her what to do. And if she's happy, I'm happy. And she's happy!"
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Meanwhile, the new couple was spotted leaving Vandal restaurant where the Republic Records VMAs after-party was held, wearing similar denim outfits as they held hands. Ariana looked very '90s in denim overalls with a crop top, choker and just one strap hooked on. Miller donned jeans and a cream colored crewneck with a bright pink baseball cap.
Over the weekend, the new couple also enjoyed a date night out with friends in the Big Apple.
The pair started off their Friday Funday at the Museum of Ice Cream where fans got a taste of the sweet fun on Snapchat. That night, they were spotted at The McKittrick Hotel where they enjoyed the hit immersive theater experience known as Sleep No More.
"She is pretty much a superfan at this point and a great guest every time," a source shared with E! News. "She enjoyed the show and spent some time afterwards on the rooftop bar Gallow Green with her guests."
The fun continued when Ariana, Mac and their friends headed to Up and Down nightclub for some late-night dancing.
"Ariana and Mac have been spending a lot of time together," another source shared with E! News. "They had a date night last night. A few friends met them out after."
Our insider added, "They were flirting and touchy feely throughout the night. It seems like they really like each other."