The Wolverhampton heavyweight was part of Anthony Joshua’s training camp ahead of his world title defence against Kubrat Pulev, which takes place in London on Saturday night.
Stewart was a sparring partner for the champion during the opening weeks of the camp in Sheffield, while he also got to work with the international fighters who arrived as preparations for fight night ramped up.
“It was a special experience,” said Stewart. “I have been in England training camps before but nothing of such magnitude, being in there with world level fighters.
“Seeing things at the start of the camp and how he (Joshua) pulls it all together. It was great to see how his mindset works and how he deals with each individual in his team.
“I also got to work with some of the coaches from the Great Britain squad. The experience has been so valuable to me. I loved every minute.”
The 23-year-old is linked to Joshua through Joby Clayton, his coach at Wolverhampton’s Firewalker gym who was first drafted onto the champion’s staff for his rematch against Andy Ruiz Jr last December.
Stewart had actually sparred Joshua for the first time back in January, after which the latter kept a keen eye on his progress before inviting him to be part of the Pulev camp, which began in early October.
Other fighters in the camp included American veteran Bryant Jennings and German giant Christian Thun, along with fellow Wolverhampton fighter Delicious Orie.
“Fair play to AJ, who saw and recognised the potential of Hosea,” said Clayton. “He wanted Hosea to experience what camp life is all about, give him a taste of what his own life could be about if he is willing to do the work that it takes to be a champion.
“Hosea has been working with the other sparring partners to get an incredibly privileged position, to see how a champion is made and forged. To see what it takes.”
It has certainly done that. A two-time Midland champion who only seriously took up the sport at the age of 18, Stewart has seen his own career put on hold by the pandemic.
With the immediate future of amateur boxing uncertain, he plans to take stock in the new year and has not ruled out a move to the paid ranks.
Yet whatever his next step, the experience of working closely with Joshua - whom he describes as an inspiration - has convinced him he is on the right path.
“It opened my eyes to show me this is my environment, I am supposed to be here,” said Stewart
“I never felt out of place at any point or under-equipped. I felt good. I had good feedback from all of the guys I sparred with and AJ himself.
“It made me realise it is a full-time thing. You have to give everything in heavyweight boxing. You’ve got to eat right, train at the right time, train consistently and set targets. I have always been a big AJ fan. He was someone who convinced me to push for it. His story made me realise if you work hard enough, you can get where you want.
“You look what he has achieved. He won the Olympics within four years of taking up the sport. Before then he didn’t know Olympic boxing existed. That pushed me to get in the gym.
“AJ is an inspirational figure. He never comes across with any ego. He has always been easy-going and open. He just told me to keep it going because it is all there. He didn’t have to say that. He has done nothing but motivate me.
“I just can’t wait to get the ball rolling now and create my own legacy.”
On Saturday, Stewart will be among the 1,000-strong crowd at the SSE Arena as Joshua looks to write the next chapter of his against the wily Pulev.
“I think I have played my part and I am just looking forward to watching the performance unfold now,” he said.
“I have never seen him fight live. So it is going to be good, different. I’m going with a few family members.
“I just want to soak it all in so in the future, when I bring the big fights to Wolverhampton, I’ll have a taste for it.”