emerson hollywood theatre date blonde

We still can't believe they are engaged!

Ashlee Simpson and Evan Ross got all dolled up to go to the Emerson Theatre last night, and it appears the couple are starting to coordinate their outfits!

We haven't heard many details regarding the pair's upcoming wedding, but we do know there's going to be one very special musical guest! And no, it won't be Jessica Simpson!

The soon-to-be groom's mom Diana Ross is set to perform at the nuptials, which are rumored to be taking place at the music legend's sprawling estate in Connecticut, E! Online reports.

We wonder which Simpson sister will become a Mrs. first?