According to Australian magazine, New Idea via Nation the couple is considering to purchase Turtle Island off the coast of Queensland and plans to build a theme park for their 17-month-old daughter.
The 23.25-acre island is worth $5 million AUD and already features a "spacious themed Australian designed home," according to Private Islands Online.
"This truly is a private Island fit for a movie star or recluse celebrity," reads the island's description on the site. "This home is perched high up on one of the handful of fully freehold private Islands on our magnificent Queensland Coast."
Richard Vanhoff, who is managing the sale, said that while he couldn't reveal the identity of the future buyer, he can "clearly say that [he is] in negotiations with an overseas party."
"The overseas party is a high profile person but I cannot name names," he added. "I can't confirm whether it's Kanye West or Kim Kardashian or President Obama."