Hannah joked that Jaime Murray's character Gaia, who joined in the prequel, is to blame for the controversial parts of the show.
"You wouldn't think the show could get any further down the line but it's shocking," he told The Sun. "It's truly unbelievable.
"There is loads of gore and even more sex. Jaime Murray is a real bad influence and she's the one that gets the House of Batiatus going. There are drugs and orgies."
Hannah also quipped that it is difficult to think of ways to keep the sex scenes interesting, saying: "You can show people having sex, but it's not that easy to find that many different ways. There are the two obvious ones - then you sort of run out of ideas.
"We got on the internet and had a look at some stuff for inspiration. But some of those positions hurt! It can be hard to get into some of them."
Spartacus: Gods of the Arena premieres in the UK on March 21 on Sky1.