Olivia Munn is getting real about her breast cancer battle … saying the diagnosis felt like slamming the brakes on her whole life.

The actress opened up in a new interview with Bustle … saying fighting cancer turned into her full-time job — and once she learned about a free test women should know about, she made it her mission to let everyone know was all that mattered.

Olivia landed her new show “Your Friends & Neighbors” after nearly five years off post-COVID … and she says she assured creator Jonathan Tropper she was fine — but was upfront about everything she’d just gone through.

Olivia says Jonathan and the whole Apple TV+ crew had her back — even pitching in with donations to breast cancer research.