General manager Matteo Mannoni admitted he did not recognise Fillion at first.
"Only the waiter did,'' he laughed.
Mannoni said the star was dressed casually and was not interrupted by other guests who might have recognised him from TV.
"He was very simple. He came in, stayed only like an hour-and-a-half, had a quick dinner and just left.
"He was with a couple of friends - there was no one outside.''
Mannoni said it was nice to have celebrities come through their doors now and again.
"Every now and then they come in, fortunately for us.''
Fillion joins a number of international actors and guest of pop culture to appear at this weekend's Armageddon Expo.
They include Doctor Who star John Barrowman, Walter Koenig of Star Trek and Babylon 5 fame, Enver Gjokaj who appears in Agent Carter and Dollhouse, Ricky Whittle of The 100 and Harry Potter's Tom Felton, who plays Draco Malfoy in the series.
