Angus MacDonald, 26, announced the news in an Instagram statement and said the diagnosis has come as a “shock” and is “hard to process”.
The Hull City footballer said he is ready to “fight” the cancer “head on” and will do whatever it will take to get back to full health.
Following his post, his girlfriend, Alexandra Burke, 31, showed her support for her beau.
The former Strictly Come Dancing contestant shared a photo of her and Angus walking together hand-in-hand from their current holiday in Dubai.
She wrote on the message: “Always by his side. Forever. @angusmac15.”
Angus uploaded a series of images of himself in his Hull City kit, and captioned it: “This is not an easy post to write but life isn’t always an easy road to navigate.
“The news broke today from my club that I have been diagnosed with Bowel Cancer.”
He continued: “After a year on the sidelines and recently getting back into full training, returning to the pitch felt closer than ever, so this news has come as a complete shock and is hard to take and fully process.”
Angus said he is “blessed” to have “fantastic family and friends” plus “amazing tea mates” who have supported him throughout the past year.
“I’m getting my head around this new challenge that lies ahead,” he went on.
“I will be ready to fight this head on, and I’m going to do whatever I can to get back to full health and back on that pitch.”
He concluded: “I’m going to take a few days away from social media, and get some alone time with my nearest and dearest. Goose x #tigers.”
Hull City released a statement on their own Instagram account, saying: “Hull City are sad to announce that Angus MacDonald has been diagnosed with early stages of bowel cancer.
“Angus has shown great strength of character in the way he has reacted to this news. The whole Tigers family join together in showing Angus continued love and will support him in his recovery.”
They added: “His physical and mental wellbeing are our number one priority at this moment in time.
“The Club kindly requests that supporters and the media respect the privacy of Angus and his family at this time. Please also note that any further updates on his progress will be provided by the Club.”
Alexandra and Angus made their first public appearance together as a couple back in July at Wimbledon 2019.
Earlier this week, the pair celebrated Alexandra’s birth with her family at restaurant Sheesh in Chigwell.
Their romance comes after Alexandra split from her former fiancé, Josh Ginnelly.
Alexandra and Josh had ben dating since 2016, and announced their engagement two years later, months after her stint on Strictly Come Dancing.