Olivia Munn wants her son to know she "fought to be here" by detailing her breast cancer struggle.

The 43-year-old actress announced in March she had undergone four surgeries in under a year after being diagnosed with an "aggressive" form of the disease, and she's now explained she has been documenting her treatment just in case she "didn't make it" so her and partner John Mulaney's two-year-old son Malcolm could read her journals at a later date.

During an appearance on 'Good Morning America', she said: "If I didn't make it, I wanted my son when he got older to know that I fought to be here. That I tried my best."

As part of her treatment, 'The Newsroom' star underwent a double mastectomy, and was then put into a medically-induced menopause, and she also had a hysterectomy and oophorectomy – procedures to surgically remove her uterus and ovaries - which she admitted has taken a toll of her body but she's determined to keep fighting.

She said: "It's so tiring. These drugs are so tiring and I know that I'm going to stay aggressive, I know I'm going to do it. It feels non-stop because it is non-stop."

The actress also underwent an egg retrieval process – which proved to be successful - before her surgeries in the hopes that she could give her son a sibling one day.

She said: "John and I had a long talk about it. We realised that we weren't done growing our family.

"Right after the mastectomy, I went through a round of egg retrieval and that's a scary process because I have a cancer that feeds off of hormones, so I knew that there was a risk.

"Our doctor said, 'Look, we're gonna get one for you and then we're gonna call it.' And then our doctor called and he said, 'Hey, so we got the results back. It's two healthy embryos.' And I, I mean, just started bawling crying. Both of us.

"We just really hope it works out for us to be able to have another baby. We just want one more. I'm not gonna ask for too much more in this life, I promise. I just want one more baby."

The 'X Men: Apocalypse' actress added as long as she had her loved ones' support, "everything else can go away".

She said: "The most important thing to me in life is my family. Everything else can go away.

"I don't have my career, I don't have my body the way that it looked before, but as long as the people I love and care about are her and healthy and thriving, nothing else matters."