The mother-of-two, 33, is said to have picked three of her closest female friends.
"She'll definitely have [sister] Ashlee Simpson and her BFF CaCee Cobb," an insider told Life & Style Weekly. "She's also chosen her stylist, Nicole Chavez."
Soon-to-be married couple Eric and Jessica
Not every decision was as easy for bride-to-be Jessica. The fashion designer and her retired NFL player beau, 34, — who plan to get married later this year — have had a few hiccups in their wedding plans.
Just earlier this month, Jessica and Eric decided to relocate their wedding to Los Angeles. The lovebirds had previously scouted out locations in Capri, Italy — a favourite holiday destination they first visited together in July 2010.
But the couple "decided to keep it simple," a source told Us Weekly, with another friend adding that they felt it was "too much" to ask guests to fly to Europe.
Jessica on a WeightWatchers advert
Jessica has shown dramatic weight loss in the past few months, which could suggest that she's getting ready to walk down the aisle soon.
The Texas-born beauty has never looked better and revealed that she had been going on WeightWatchers to shed her post-baby pounds, after giving birth to son and second child Ace last June.
Jessica and Eric's nuptials were put on hold with the near back-to-back births of their children.
"We don't have an actual date but we do know that we want it to be this year," Jessica previously told Good Morning America. "We need to get married."
Bridesmaid-to-be Ashlee and Jessica
The television personality is not the only bride-to-be in her family.
Younger sister Ashlee announced her engagement to Diana Ross' son Evan in mid-January, and recently celebrated her imminent nuptials with a lavish engagement party.
Inside Ashlee and Evan's star-studded bash
Ashlee and Evan looked the picture of happiness as they were surrounded by their nearest and dearest, who included Jessica and superstar Diana.