In a sport where training partners often refuse to face off for real, the Treadwells aren't letting the bond of blood get in the way of their pursuit of mixed martial arts.
Mike Treadwell, who like Thomas will be making his pro debut, inquired about fighting in the Edmonton-based Maximum Fighting Championship. During that conversation, he mentioned he had a younger brother who was also looking to try his hand at MMA.
Scott Zerr, the MFC's director of media and fighter relations, suggested they fight each other.
"They jumped at it," said MFC president Mark Pavelich.
Mike Treadwell, who at 30 is nine years older than Thomas, says the brothers' initial reaction was slightly more circumspect.
"At first it sounded like a fun idea," he said. "Then after we started talking about it a bit, we kind of weighed out the pros and cons and then we decided to do it. Just because it's something fun and it will be something that we can say we've done.
"A lot of people say that they would like to do it and we can say we've actually done it."
The brothers will face off on the undercard of "MFC 37: True Grit" in their hometown at Edmonton's Shaw Conference Centre.
The main event, a heavyweight title fight between American Chris (Beast Boy) Barnett and Calgary's Smealinho (The Prince) Rama, was called off Tuesday after Barnett failed his medical.
The MFC said tests showed the American MMA fighter had three holes in his retina.
The sport is no stranger to brothers. The UFC has been home to the likes of Nick and Nate Diaz, Antonio Rogerio and Antonio Rodrigo Nogueira, Jim and Dan Miller, and Joe and Dan Lauzon.
Other brother duos include Alistair and Valentijn Overeem, Fedor and Alexander Emelianeko, Michael and Brad McDonald, and Anthony and Sergio Pettis.
But usually brother corners brother. Not brother fights brother.
Pavelich says he understands brotherly spats.
"When I was growing up, my brother and I would start fighting in the basement," he said. "It would go outside, it would go around the block and come back to the front yard of our house. And my father, who was a referee in the NHL at the time, could not break me and my brother up when we used to fight."
The fight has drawn plenty of interest, far more than a fight between two novice pros would normally warrant.
Mike Treadwell, who stands 5-10 and weighs 220 pounds, says his circle of friends understands why the brothers are fighting.
"They understand that it is a sport and it's a competition. It's not a fight, we're not angry at each other," he explained. "It's a competition and a lot of people are excited, looking forward to seeing it."
Thomas Treadwell, through the MFC, declined an interview request.
"I think the response is so overwhelming for him that's he's just not used to it," said Pavelich.
Mike Treadwell also admits to being surprised by the interest.
"I knew there would be some but not as wide as it's happened," he said. "I didn't realize that as many people would focus in on it."
He declined to discuss his family's thoughts on the brotherly bash. An earlier MMAjunkie.com story indicated that the parents were not in favour of the fight.
There are two other brothers in the family, aged 20 and 24.
"We're really close, we're best friends. All of the brothers are best friends," said Mike Treadwell.
The brothers rarely fought growing up, he noted.
"I was never physical with any of my brothers really," he said. "Sure pushing around, telling them be quiet and stuff like that. But never physical altercations being so much older than all of them.
"We've disagreed on things a few times so you'll sort of ignore the other person for a bit but it doesn't last longer than a day. It goes away and we're fine again."
Pavelich says the reaction to the fight has been generally positive. Those against it thought it "gimmicky," he added.
Pavelich says that's not his style and that he made sure both bothers had trained in MMA.
Mike Treadwell has a background in wrestling and amateur boxing and was also in the military.
He has been training in MMA "off and on" since about 2000 and going at it seriously for the last six months.
Thomas Treadwell, who is five foot nine and 230-235 pounds, is newer to the sport.
"He has skills," said his older brother, who works as a manager for a transportation rental, sales and services company.
"I don't think he's actually ever trained in anything until now. He's got a good standup game."
The two brothers have been training separately, other than cardio and weight-lifting workouts.
And the brothers seem to be getting on fine, so far.
"We talk about it, almost on a daily (basis) ... It's nothing that's pushing ourselves apart at all," said Mike Treadwell. "It's making us closer if anything. It's really good."
In fact, he can't wait for the battle to begin.
"I'm really excited about it," he said. "I actually find myself dreaming about it at night. And I keep waking myself up thinking what day it is. It's not (fight time) yet."
He he wouldn't mind fighting again.
"If I'm given the opportunity to do it again, I will," he said. "It's something that's always intrigued me and I've always wanted to do. And now, I'm 30, it's a little late to be starting in it but the opportunity presented itself and I'm taking it."