The Keeping Up with the Kardashians star took to Twitter at the weekend to respond to a follower's question regarding the colour of the dresses.
"GREEN!" Kourtney replied.
Kim recently confessed that she was afraid she would have to walk down the aisle alone at her upcoming wedding, after her father passed away in 2003. However, Kim's stepfather Bruce Jenner will give her away instead.
Kim is engaged to NBA star Kris Humphries. The couple will wed in California on August 20.
The American socialite recently revealed that Vera Wang will be creating her wedding gown, saying that the renowned designer is a close friend of the family.
Tyra Banks has described the dress in question as "beautiful" and insisted that Kim will look gorgeous on her big day.