The 8,520 square foot pad is the former home of pop star Rihanna, who moved out in 2011.
Despite the home already having a theater, a billiard room and a gym, the couple has added their own renovations to make it more modern, the insider detailed.
Why the big rush to finish renovations? Because they have a big arrival coming soon!
“We're trying to get the house ready before the baby gets here," John told ET on Friday. "I don't know if we're gonna get done in time! But we're gonna live in a house that's at least, you know, 90 percent finished by the time baby's here."
Chrissy seems to be getting work done around their former home, posting an Instagram on Friday of her bulldog in a seemingly empty house.
“He keeps just showing up in random spots and farting,” she captioned the pic.