Joanna Krupa Lord of the EIGHT CARAT Ring!

8/6/2009 2:05 PM PDT
Smokin' hot Maxim model Joanna Krupa's fiance didn't just put a ring on it -- he put a small fortune on it.

Krupa was showing off her new accessory outside Katsuya last night, and told us her man dropped enough dough to get her 8.23 carats!

We're told by experts in the field of ice that a high quality 8 carat diamond can go for upwards of $1.5 million on the retail market -- but look at what he goes home to every night ... worth every penny.