Are Joshua Jackson and Diane Kruger Engaged?!

Find out why there's buzz that the hot couple may be getting ready to say "I do"

Could Joshua Jackson and Diane Kruger be planning a wedding?

The Fringe actor, 33, set off some may-be-headed-to-the-altar buzz last night at the posh "Nights in Monaco" gala benefit for the Prince Albert II of Monaco Foundation and the William J. Clinton Foundation at the Hôtel de Paris.

Not only did he pay $45,000 for a necklace with 11.7 carats of white diamonds set in 18-karat rose gold during the evening's live auction, but...

"He said he was looking for the 'perfect engagement gift,'" a fellow gala attendee tells me.

Kruger, 35, was by Jackson's side when he placed the winning bid, having skipped over to Monte Carlo from the Cannes Film Festival. She stunned in a Prabal Gurung gown.

The gorgeous couple have been together for about six years.

Kruger's rep says they are not engaged and Jackson's rep insists he never made any comments about searching for an engagement gift

Kruger, whose first marriage ended in divorce, told Glamour magazine in 2011, "Without sounding pessimistic, I learned that I don't believe in marriage. I believe in a commitment that you make in your heart. There's no paper that will make you stay. A guy friend of mine said, and it made a lot of sense, that people should get married at the end of the road, not the beginning."