The entertainment series is based on a US TV format devised by Jerry Seinfeld, which features real couples sharing their marital issues with a studio audience and a panel of famous faces.
"The Marriage Ref takes a close look at everyday disagreements faced by couples - something we can all relate to and laugh with," said ITV1's commissioning editor for comedy and entertainment Claire Zolkwer.
James Corden, Jonathan Ross and Geri Halliwell are among the celebrities taking part in the show along with comedians Alan Carr, Jimmy Carr, Sarah Millican and Micky Flanagan.
The X Factor presenter O'Leary was confirmed as the programme's host in May.
Zolkwer commented: "It's an entertaining format and Dermot O'Leary will make a great host, not only giving his opinion but also leading the debate amongst the panel."
The Marriage Ref airs at 9pm on Saturday on ITV1.
Watch two clips of The Marriage Ref below: