Bleakley is running in Blackheath on July 1, the same day that former Emmerdale star Pallett runs with her mother and auntie in Bolton. Range runs today (June 24) at Aintree, near where she grew up.
Before their runs, Range and Pallett spoke to Digital Spy about why they decided to join the event, which hopes to raise a total of £55 million, some of which will be donated via Vodafone's JustTextGiving service.
"Unfortunately lots of people have been touched by cancer," Range said. "I lost my grandad to cancer, so me and my mum are running the race at Aintree Race Course.
"It's a really good cause and hopefully will raise a lot of money. It's in memory to people and hopefully will do good things for people who are ill now.
"I think it will be quite emotional, but everybody I've spoken to who's done it has said it's really uplifting as well."
Pallett agreed: "It's a celebration between everyone who's gone through the same thing.
"It's a really amazing campaign that unites a lot of people. We all know all know someone that's either died from cancer or is fighting cancer at the moment."
Of how seriously the girls will be taking the racing aspect, Range told us: "There'll be a lot of fancy costumes - my mum's going in bunny ears and a tutu.
"I guess I'll have to put something on or I'll look like a bore, mightn't I? Any excuse for fancy dress really!"
Pallett added: "It's not too serious a race - you can walk it, you can get fancy dress - it's nice for all the family to do together.
"We would never do the marathon. We're not fit enough and we're not sporty people, but we wanted to do this for my grandma's memory."
Asked if she and her family had done any training, Pallett said: "Yeah, the three of us have been doing power walks, it's hilarious! We usually end up in a fit of giggles.
"It's funny the three of us doing it together. It's that camaraderie, when you're doing it with other people, you keep going."
She added: "I've said to my mum, it doesn't matter how long it takes you or if you need to walk it. It's not about that.
"There's no competitive side to it. It's just about doing it and turning out for the day and everybody sponsoring you.
"I just think it's a really special day and it happens all round the country which is nice, so there's always somewhere near where you live which is hosting a Race for Life."
People wanting to donate to the girls can text their personalised code and an amount to 70070. There's no cost for the message and 100% of the money donated goes to the charity.
The codes for each woman are as follows: Christine Bleakley - CHRS81, Roxanne Pallett - ROXY82, and Heidi Range - HEID83.
JustTextGiving by Vodafone is the official donation partner of Race for Life. To start fundraising with a free personalised text code visit Vodafone.