Megan Thee Stallion Gifts BF Moneybagg Yo $150k Heart Jewelry

Megan Thee Stallion's getting serious with her boyfriend/fellow rapper by buying him a seriously expensive birthday gift ... with a pretty romantic message attached.

The "Hot Girl Summer" rapper gifted Moneybagg Yo with a blinged-out, half-heart pendant. As you can see, there are 2 chains with 2 half-heart pendants -- his and hers.

Before ya start thinking the half-heart pieces are kinda basic, know these didn't come cheap for Megan. The complete set includes 120 grams of 14-karat rose gold and 40 carats of VVS diamonds blanketing the pendant.

Translation: Serious drip!!!

The pieces -- created by celeb jeweler Iceman Nick -- also feature exposed ribs finished with red enamel. We're told the full package cost Megan $150,000.

She gave Moneybagg his bday gift before their joint club appearance last Monday in Atlanta. He happily flaunted it -- and Megan too -- on social media as they partied the night away.

A happy 28th, indeed, for Money!!!