The 31-year-old has overcome both testicular and lymphoid cancer to fight back to full fitness and resume his career as a professional player.
Now he wants fans to really get behind Tackled Pink this weekend help raise awareness and funds for the UK's leading breast cancer support charity, Breast Cancer Care.
"I think the Tackled Pink theme is really fantastic," said Horsman. "The whole Guinness Premiership has really bought into it which is magnificent. We can truly raise awareness and that is crucially important with illnesses like cancer.
"I have seen people get embarrassed about the whole situation because it is such a serious illness. I think people almost shy away from it. It's important for people to say the word cancer and not get embarrassed.
"Supporters have obviously spoken to me about it in the past and my experiences, people ask me the question about it but you see them mulling over in their mind how their going to breach the subject.
"People must not be afraid to speak about it and be open about it so Tackled Pink is huge."
Warriors will be playing their part with a 'Pink & Proud' competition for the best dressed fans and 'The Warrior' match day programme has a special pink theme with a pink 'Try Time' poster in the middle pages.
The club is also hosting a Pink 'n' Gold Gamble, Pink Bar in the East Stand, special stalls for women coming to the game in the South Stand.
The touch rugby demonstration at half-time will have a pink theme, the Warriors Allstarzz will be dressed up for the occasion and fans can even win a car - wrapped in pink - by guessing the registration plate.
Horsman is delighted that the Guinness Premiership is coming together to raise vital awareness and believes it can have a huge impact on making cancer a subject people feel they can talk more openly about.
"The more people we can get talking about it the more likely people are going to their doctors and checking themselves and take the right attitude to it," he said.
"I know it can be very private and personal, but you just have to have a liberating attitude towards it and not be afraid to talk about it.
"People who have had it or suffer from cancer get quite frustrated because it can seem people don't know how to breach the subject. But once you have had a disease like that, myself personally, you change as a person. You can almost say you have pre-cancer life and your life afterwards.
"You may get physically better but it never goes away. Once you have experienced something like that, when a doctor tells you may not survive and you have hugely invasive treatment, it sticks with you, it really shapes you personality.
"But it helps when people are not embarrassed by it, it shouldn't be a taboo subject and hopefully Tackled Pick will help raise awareness, funds and the wonderful work of Breast Care Cancer."