Ashlee Simpson and fiancé Evan Ross celebrated their engagement with a party for their friends and family on Wednesday night, March 26.

As expected, the Hollywood couple went all out in eccentric attire for their big night. Simpson wore a patterned caftan with a large feathered headpiece, while Ross sported a fur coat and diamonds. After all, this is Diana Ross' son we're talking about.

Simpson shared a photo of the occasion on her Twitter account to express her excitement.

What an amazing engagement party with all of our loved ones! We gettin' married :) pic.twitter.com/xdQLFerlIk

- Ashlee Simpson (@ashleesimpson) March 27, 2014

Ashlee's famous older sister, Jessica, was among the attendees at the lavish soirée. The singer posted a photo with her sister on her Instagram account, saying, "Celebrating my best friend and sister @missbananahammock @ashleesimpsonofficial. I love her so much!"

The night was made extra special by the fact that it happened to be Diana Ross' 70th birthday. According to E! News, the Motown star is incredibly involved in her son's life and has taken a lead role in planning for both the engagement party and wedding.

We can confidently say that this will be one fabulous wedding.