The Assets model revealed to the Herald that the series producers found her picture online and asked her to star in the show, playing a new mistress of the king.
"They scouted me out online. They were looking for a girl with long dark hair. I will be playing the king's mistress on the side for a few days. I can't wait," she revealed.
Lisa (21) will be shooting her scenes for the show this week. And although the popular series is known for raunchy sex scenes, the Dublin model says she refused to strip down for her upcoming episodes.
"When I got hired for the part I was told that I would be topless and I wasn't happy about that at all.
"I would never do something like that I have to think of my family."
Despite agreeing to cover up, Lisa says her boyfriend is not too happy about her upcoming appearance.
"He is extremely worried as he knows it is quite a raunchy show, I'm not doing any sex scenes but he is still quite concerned," she said.
The Lucan native will now be rubbing shoulders with the likes of actor Sean Bean and 300 star Lena Headey.
Lisa revealed that she will be filming scenes on the official Game Of Thrones set on the coast of Belfast.
"I just had a fitting and I met all of the cast. We are shooting inside a castle."