It was announced earlier this month that the actor will play Michael Sainte, a "spiritual marketing guru" on the HBO drama.
"Margene (Ginner Goodwin)... was working for a QVC kind of channel [but] is no longer working for them because Bill and the family are out now and she lost her job," Show explained to Fancast. "I play a networking marketing sales guy... and I bring her in."
He refused to confirm whether the two characters will begin an affair, but admitted that Michael will clash with Margene's husband Bill (Bill Paxton).
"I've been a huge fan of Bill Paxton since the '80s," he explained. "Getting to work with him in an adversarial way, where I get to step up and get in his face, was really fun."
The final season of Big Love airs on Sundays at 9pm on HBO.