Ariana Grande caps off a HUGE engagement surprise with an even BIGGER engagement ring

Gelo Lasin

Ariana Grande is engaged to new beau Pete Davidson after dating for almost a month. A MONTH.

The engagement comes off only after a few weeks of dating for the couple, who hooked up on May 18.

Ariana’s was previously with rapper Mac Miller…

… and Davidson was with longtime girlfriend Cazzie David.

“They’ve been very public with their relationship on social media, and they are very in love.” a source close to the couple said.

If that wasn’t enough of a bombshell, then here comes the nuke – WE HAVE DETAILS ABOUT THE RING

Davidson splurged $100,000 for the custom-made ring

The diamond is more than 3-carats (aka a lot) and is set in platinum.

The dude who made the ring – Greg Yuna –  claims Davidson ordered the ring back in May.

Which means the SNL star met Ariana, dated her for maybe a day, THEN decided he wanted to propose?

But hey, if you’re in love, you’re in love. Here’s to more crazy, whirlwind romances!