The pair locked arms while walking around the park looking happier than ever, with photos you can see at DailyMail.com.
But they weren't alone! It looked as if they were on a double date with friends.
Mikey didn't leave the singer's side, with his arm folded in hers as they walked behind a VIP guide.
A source told the publication: "Ariana stayed close through the night, never keeping her hands or arms off of him."
Earlier that day, Ariana showed on her Instagram story that she was in the studio with Mikey.
Ariana's brother Frankie Grande was the first to confirm the romance in September last year when he revealed that he and his partner Hale Leon go on double dates with Ariana and Mikey.
Frankie spoke to some reporters at The Game Changers premiere in Los Angeles, saying: "I love Mikey, I think he's a really sweet guy. So talented, so kind and so caring, he's a great guy.
"We had a double date night the other night, it was a lot of fun. [It was a] game night with board games. I'm excited to go spend quality time with all of them."