Carlton and Collingwood may be arch rivals on the footy field but they are united in support of cancer research at Peter Mac.

When these two great clubs run out on the MCG this Sunday - for a sell-out game that will shape the footy finals - they will also compete for the Richard Pratt Cup which is used to highlight prostate cancer, now Australia's most commonly diagnosed cancer.

All monies raised by this "Clash for a Cause" game will be used to advance ground-breaking research underway at the Prostate Cancer Theranostics and Imaging Centre of Excellence (ProsTIC), at Peter Mac. 

Both clubs also invited Peter Mac patients to visit their facilities and to meet the players this week. 

Patient James Snape - a life-long Collingwood fan - said it was an "incredible day - training was great to watch and it was awesome to meet all the Collingwood players and chat". 

 WATCH: See James' visit to the club below.

"The staff showed me around the club and I even got to hold the 2010 premiership cup which was pretty surreal," James said. 

"It was a really fantastic day and I’m very thankful to have gotten the opportunity to experience it all through Peter Mac."

Patient Ian Langford - and his sons and grandsons (three generations of Carlton fans) - visited Carlton to chat with Sam Docherty and also tour the club.

This game is also used to highlight men's health issues and, at a pre-game press conference, Carlton's Sam Docherty talked about his own successful cancer treatment.

He called on Australian men to be more proactive about their health as this is the key to finding cancers early when they are easier to treat. 

"The message I would say to men more broadly and anyone really is make sure you stay up to date with your doctor's checks," Docherty said on Tuesday.

"I think men try and hide from the doctors when they have an ache or a groan: That can be the difference between saving your life or losing your life if you catch it later than you should."

"We hide the fact that we might be struggling, that’s not the way to go about it. So I’d just encourage everyone to go and see the doctor and if something is wrong, you can get it treated if you go early enough." 

WATCH: See Sam Docherty's full press conference below, including opening comments from Peter Mac's Chief Executive Professor Shelley Dolan.

More than 24,000 men are expected to be diagnosed with prostate cancer during this year.

You can donate to support prostate cancer research at Peter Mac, and give new hope to all those affected by prostate cancer, here: https://prattcup.petermac.org.au/