The Four Weddings and a Funeral star plays Batiatus, the owner of an ancient gladiator academy, who romps with his onscreen wife Lucretia, played by Lucy Lawless.
But he admits it took a lot of work to depict a Roman orgy as he struggled to think up new sex moves.
Hannah explains, "There is one scene where we have an orgy. It's shown as a kind of cool, drug-induced montage, so we needed lots of different sexual positions. 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. It was kind of interesting."