Uma Thurman and Arpad “Arki” Busson

Uma Thurman is planning a wedding!

Uma is engaged to her Swiss multimillionaire boyfriend, Arpad “Arki” Busson. Apparently, he is super-duper-rich. Uma knows how to pick ‘em!

The details on Uma’s engagement ring: an 8-plus carat center stone surrounded by 20 smaller stones. “It’s the most beautiful piece I’ve ever seen,” says a close source of the diamond ring. “Arki did a wonderful job.”

It would be the third marriage for Thurman, who has a son and daughter with ex Ethan Hawke, whom she divorced in 2003. Her marriage to Gary Oldman ended in 1992. Busson has two sons with former supermodel Elle Macpherson, from whom he split in 2005.

Congrats to the happy couple!