If getting some valuable rounds and experience against fellow Morecambe fighter and world title contender Isaac Lowe is not enough, the lightweight ace often find himself benefiting from a few pearls of wisdom from non other than WBC heavyweight champion of the world Tyson Fury.
Living in the same northern Lancashire town, the three have over the years become firm training buddies.
At 26-years-old and with 15 bouts to his name, MacMillan is the younger and least experienced of the trio but that’s not to say he does not carry the same drive and determination of his more illustrious stablemates.
Indeed, seeing Fury become arguably the best pound-for-pound fighter in the world and a modern-day great has inspired MacMillan to be the best he can be.
It certainly beneficial for him to be working in such close quarters as Fury and Lowe.
Last Saturday Fury had a glorious homecoming when he defeated British rival Dillian Whyte in front 90,000-plus spectators at Wembley Stadium.
For his part, MacMillan is also preparing for a big outing on Saturday when he appears on the undercard of Jack Massey’s WBO cruiserweight world title defence in Bolton.
"I spar a lot with Isaac,” said MacMillan. “Tyson is always giving me advice. He sometimes stands in my corner when I’m sparring with Isaac and gives me advice.
"He will give me little bits of information to try out and just basically little things which can help me improve in certain situations.
"It’s kind of crazy to think that I am there in the same gym with the heavyweight champion of the world.
"He’s known the world over but he’s still so down to Earth – he is still the same person.
While MacMillan has a long path ahead of him before he can be mentioned in the same breath as the pair, by working closely with those two, he has witnessed at first hand just how far hard work and determination can take you in the sport.
At 26-years-old he believes his best days are still to come and sees no reason why he can’t fight for big titles in the future.
Having won 14 out of 15 bouts so far – his one loss coming against the vastly more experienced Kirkham fighter Adam Little early in his career – MacMillan believes he is starting to build momentum.
He has won his last 10 bouts, including three victories since returning to the ring following the Covid-19 pandemic.
"I definitely want to win a British title and anything else that comes after that will be a bonus,” he said.
“I open for anything – I will take any opportunity that comes. I was the mandatory challenger for the central area title before Covid hit and scuppered that.
"It maybe that I go above that and look to fight for the English title this year.
"It is a bit of a waiting game but I don’t want to be waiting around for fights.
"I want to keep fighting and then when an opportunity comes around I will be ready.”
MacMillan has new direction in his career after being signed up by respected Lancashire manager Kevin Maree.
And he has also linked up with trainer Bob Howard, who he worked with as a youngster.
His partnership with Howard has come under sad circumstances as his previous trainer John Donaghy passed away in 2019.
"I was with Bob as an amateur,” he said. “I was with John before that but sadly he passed away after an heart attack.
"I have been with Bob a few years now and feel like he has improved me loads.
"I’ve not lost a round since I have been with Bob. "Kevin’s been a really good manager. He sticks to his word and makes sure you get opportunities.
"He says he’s got high expectations for me and sees potential in me.”
In his last outing, MacMillan got the better of Des Newton, outpointing the 33-year-old at the Colne Municipal Hall. His next opponent is unconfirmed but is expected to be a step up in class.
"I have got this fight coming up fighting on the undercard of Jack Massey’s world title defence,” he said.
"The bill is being shown live on television which is good. It's a chance to show people what I can do.”