Mac Miller on How His Friendship with Ariana Grande Evolved Into More: 'Everything Just Happened Organically'

"We love making music together," Mac Miller tells PEOPLE about his friendship-turned-relationship with Ariana Grande

Photo: Chris Phelps for AUDIENCE Network

Ariana Grande called him ‘boo’ at the 2016 MTV Video Music Awards, confirming Mac Miller’s relationship with the singer. But when did it all start?

The rapper reached out to Grande when he thought she would be a great artist to feature on the track “My Favorite Part” on his fourth album The Divine Feminine (out Friday).

“I wrote that love song before I saw her. We’re very good friends first and foremost,” Miller told PEOPLE at the taping of the AT&T Audience Network Presents series on Monday. “We made that song and started becoming close again. It’s very dope and I like how that worked out.”

Miller, 24, and Grande, 23, had previously collaborated on her hit song “The Way”, so it wasn’t the first time they’d worked together, but in this session it was like no time had passed.

“It was great. There was no awkwardness or weirdness, it was how it always was,” the rapper continued. “Just both of us older, more mature and more sure of ourselves. When we first recorded together we were young and figuring it out, which we still are, but now seeing her growth and my growth – it’s great.”

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The two performed “My Favorite Part” at the weekly music series and their chemistry was fierce. At the end of the song, Grande shook Miller’s hand, as though to thank him jokingly for doing business with her, and walked off stage.

“Pleasure working with you,” he said, to which she replied: “I’ll be in touch.”

After the cameras stopped rolling, Grande went back on stage to put her hands on his shoulders and they shared a sweet moment. She cupped his face in her hands, leaned in and kissed him, at which point Miller kissed her right back.

The two love making music and spending as much time together as they can, so it makes sense that the relationship was a natural progression of their friendship.

“We hung out for a long time and everything just happened organically. We love making music together – we do that always. But she’s my best friend in the world.”

And Miller enjoys their time together on stage as well. “We’ve performed together a lot – when “The Way” came out, we did all the shows,” he said. “We’re both relaxed – we just have fun. And everybody gets an ‘awww’ moment.”

The “awww” really comes in when he describes Grande to others.

“She’s just very warm and comforting,” he said. “She’s very caring but, also, we have a lot of fun. We go on adventures. Adventures can be driving around in the car aimlessly. It’s great to be able to do nothing and be doing so much.”