Once a lightweight but more recently operating at welterweight, McAllister is moving up a full 60 POUNDS to face Williams in a July 28 event in Scotland.
Williams, 45, is a massive favorite to overcome the home fighter and in the process extend his four-fight winning streak.
“There will be no losing, it’s going to be all winning. I’m going to beat him and knock him out. I don’t think Lee quite knows what he has let himself in for,” Williams told the Evening Express.
“I’m telling you from the first round he will regret what he has done, he will regret taking this fight big time.
“That’s my message to Lee and his fans – you will regret it, no doubt.”
On what gets him up out of bed and back in the gym despite his veteran years, Williams added: “The motivation is money firstly and also it is a former lightweight I’m fighting.
Credit: Kath Flannery / Evening Express
“The cheek of it that a former lightweight is challenging a heavyweight, that’s massive disrespect and cheeky so I’m going to put him in his place for that.
“I feel really good and I’m ready to rumble in this fight.
“I’m not giving Lee McAllister credit for that because I had a fight scheduled for a few weeks ago which was cancelled.
“So I was training for that and I was in shape. Lee will be punished for that,” he added.
McAllister has piled on as many pounds as possible for the Williams clash, which is largely seen as a publicity stunt more than an actual contest.
Many outsiders looking in believe McAllister could get seriously hurt for his endeavours to face Williams, whilst there’s a hometown minority who see the Aberdeen man’s youth as the key to the former Commonwealth champion pulling off one of the biggest shocks in Scottish boxing.