Pitt, 48 raises six children Maddox, 11, Pax, 8, Zahara, 7, - and three biological children - Shiloh, 6, and four-year-old twins Knox and Vivienne with Jolie.
The actor says now it is not just about the broods forcing them to tie the knot but he also wants it to happen, reports thesun.co.uk.
"I am getting more pressure from my kids, and it is something I want to do within their lifetime, but I also feel like the time has come," Pitt said.
"The time is nigh. It's soon. I got a good feeling about it," he added.