Bentham’s rising light-heavyweight takes on Barrow’s Liam Conroy at the Manchester Arena on the undercard of Anthony Crolla’s world title unification clash against Jorge Linares.
The fight is the big break Tatham has been waiting for and has been sanctioned as an eliminator for the British title.
The 27-year-old said: “It’s going to be the biggest night of my life.
“This is what I got into boxing for.
“It’s a massive stage for me but I’ve just got to keep professional and keep focused.
“It’s just the same as ever. It’s the same ring and we’re both there to win.
“I just want to go out there and impress and get people talking about me.
“This is my night and hopefully everything just follows from there.”
Tatham is no stranger to his Cumbrian opponent, the pair having sparred together as amateurs.
Their careers are now on a similar trajectory, Tatham blasting away Eric Mokonzo inside five rounds in March to land the International Challenge belt, the 11th win of his career and fifth inside the distance.
Conroy also has designs on facing unbeaten British champion Hosea Burton, who meets Frank Buglioni on the same night, with the 23-year-old having landed the WBC Youth Silver title last month in Preston with a fourth round stoppage win over Ferenc Albert.
Tatham said: “He’s in a similar position to me.
“We’re both up and coming and we’re both hungry.
“I know him. We sparred a lot as amateurs and just had wars.
“He’s a good boxer and a nice lad.
“It won’t affect me though. It just means things will be a bit more chilled in the build-up and there won’t be the animosity.”
Being part of the Matchroom-promoted show means Tatham will experience big-time boxing for the first time after grafting on small halls thus far.
He said: “I’m really looking forward to fight week.
“It’s going to be great to have a big weigh in and sit at the top table of a press conference.
“As much as I’ve got to try and keep things the same it’s going to be different.
“Hopefully after September 24 it’s going to be the norm though.
“I’ve done my apprenticeship and this is the start of the real work.”
The night is set to be the biggest night in Lancaster and Morecambe boxing history with Westgate Warrior Isaac Lowe also defending his Commonwealth Featherweight title against Tshifhiwa Munyai on the Sky Sports-televised bill.
For tickets call Tatham on 07903 809293.