The Yes Man actress announced her engagement to Battleship producer Scott Stuber in June.
Sims joked that she will host a star-studded ceremony which will even include musical numbers performed by the guests.
"It's an entire wedding filled with celebrities. It's the wedding of the century. They are all celebrities, and they are all singing!" she told E Online.
Sims also praised her wedding planners for helping her put together her dream day, adding: "Yifat Oren and Stephanie Cove are the single best wedding planners in the United States. Hands down. Their whole mantra is, like, perfectly messed up. It's amazing."
The actress revealed in 2009 that she feels ready to start her own family either via adoption or by giving birth to her own children.