It's the kind of call every parent dreads, and it couldn't have come at a worse time for news presenter Rachael Bland.

She had just bought ice cream for her two-year-old son, Fred, and was watching him play on a tire swing when her phone rang.

"'I am so sorry,'" the voice on the line said. Bland's cancer had returned, and this time it was terminal.

But the awful news inspired the mother to leave behind an incredible legacy for her son.

"I don't know how long I have left and I just really wanted to leave something behind for him."

Bland, 40, is a presenter for the BBC. She was first diagnosed with breast cancer in 2016, and has been fighting the disease ever since.

Through a mastectomy and multiple rounds of chemotherapy, Bland stayed hopeful. Even after she began to rely on an oxygen tube to breathe.

Bland even volunteered to be a "guinea pig" for new, experimental drugs.

But in April, after the cancer had spread to her lymph nodes, Bland got the news she had always been dreading.

Like any parent, her first thoughts were for her child.

"I was just watching Freddie playing so innocently in the barn and I thought, "˜My poor, poor Fred,'" she said.

Realizing she would not be around to watch her little boy grow up, Bland decided to leave a gift behind so she would always be with him in spirit.

"I don't know how long I have left," she explained, "and I just really wanted to leave something behind for him."

"Imagine him growing up without remembering who I am."

Bland is writing a memoir about her life, titled For Fred, to share all of her memories, wisdom, and love with her son after she's passed away.

Even though Fred has Bland's husband, Steve, to look after him, that wasn't comforting for her.

"As he grows up he'll get all the stories about me from my husband Steve. But he doesn't remember them all in the way that I remember them," she said.

"I hope he can read my personality off the page and hear my voice through it."

Bland revealed that she hasn't actually discussed her diagnosis with Fred, so the book will hopefully help him come to terms with it when he's older.

"Freddie's too young to understand so I've not had that conversation with him," she explained.

"I think, "˜Imagine him growing up without remembering who I am.'"

"The only time I get really upset is when I'm looking at him and these thoughts pop into my mind. I think, "˜If he's upset about anything, what will he do if I'm not around?'"

"Grab every opportunity you can and keep on trying."

While her project is just a week old, Bland says she has already typed out more than 12,000 words, with a lot more to come.

"I'm five chapters in and I've not got to where I got pregnant with him," she said.

"The last chapter will be a closing message to Freddie, which will be difficult. I want him to know he can be whoever he wants to be and do whatever he wants to do and I'll be proud of him."

Bland, who shares her cancer journey in the podcast You, Me & the Big C, has already shared some of the wisdom from her memoir with her fans.

"Try not to take things to heart too much," she writes.

"Feel and grieve your disappointments because not everything can go your way in life, then get back out there again and carry on living."

"As I now know only too well, you only get one chance at life so grab every opportunity you can and keep on trying."

She also shared some all-purpose life advice with Fred in a section on job hunting: "But remember, you are here to make yourself and those around you happy, so always keep that in mind."

Bland hopes that her finished memoir will be published, so that other parents and relatives of cancer patients can benefit from her insights as well.

"Even in this awful situation, facing a terminal diagnosis, good things can still come of it, and you can still live and enjoy life," she said.

You can continue to follow Bland's story on her blog.

Here are more heartfelt parenting stories:

• Pink gets real about parenting on Reese Witherspoon's new show.
• Stepmom's photo proves there's no such thing as a "broken" home.
• After his daughter's report card left her in tears, this dad stepped up.

[H/T: Honey9, Daily Mail, The Sun]