The magazine features original strips including the world debut of Millar and John Romita Jr's Kick-Ass 2: Balls to the Wall and comedian Frankie Boyle's Rex Royd.
It also reprints Jonathan Ross and Tommy Lee Edward's Image Comics title Turf and Millar and Steve McNiven's Nemesis.
"What really excites me is the gap I see in the UK market at the moment," said Millar.
"There are absolutely no comic books aimed at the 16 to 30-year-old guys and I think CLiNT has the potential to make an enormous impact, bringing a new type of magazine to a new generation."
Millar and Ross will be signing copies of the magazine at WHSmith in London's Victoria Station from 4.30pm today.
> Click here for our recent interview with Mark Millar