Look closely ... WWE diva Kharma's new engagement ring is actually two in one -- a ring ... ON A RING -- and TMZ has obtained a pic of what might be the coolest piece of jewelry ever forged by man.

Sources close to Kharma -- real name Kia Stevens -- tell TMZ, the diva's fiance popped the question a few months ago ... and with a rock like that, it's no surprise she said yes.

No date for nuptials has been set ... but we're told Stevens (left) -- currently on maternity leave from the WWE -- is planning to tie the knot in June.