The pair clash on December 11 at the Liverpool Echo Arena in a mouth-watering domestic dust up.
It is part of Frank Warren's Return of the Magnificent Seven card which will see multiple title fights on offer.
Home fighter Smith has already boxed 29 times as a professional, completing 148 rounds.
By comparison, Olympic 2008 champion DeGale has racked-up eight pro contests with only 21 rounds under his belt - and has yet to go six-rounds.
"It's going to be man against boy," said Smith.
"I've done 12 hard rounds in my last two fights, more rounds than DeGale has done in his life.
"Experience is the key in this one, and I've got so much more of it than DeGale.
"I'll know exactly what to do in there when the going gets tough - and believe me it will get tough - but James will be asking himself 'What do I do once it goes past six rounds?'
"This is the kind of fight where one guy gets taken into deep waters where he has not been before.
"And believe me, DeGale will find the waters very deep once we get into the second half of the fight.
"He tells everyone how fit he is, and how he can do 12 rounds no problem in the gym.
"Now we we will find out. I'm sure he can, but there is a very big difference between sparring 12 rounds and fighting hard for 12 rounds like I had to do against Dodson and Quigley.
"I've got the ability to beat DeGale, but I've also got the experience to beat him as well."
Tickets for the Return of the Magnificent Seven, priced at £40, £50, £100, £150 and £250, are available from:
The Liverpool Echo Arena
0844 800 0400
www.echoarena.com
Ticketmaster
0844 844 0444
www.ticketmaster.co.uk
See Tickets
0871 220 0260
www.seetickets.com