However, after nearly a year of keeping their romance on the down-low, the pair stepped out together on Wednesday for their movie premier "Ondine" at the Tribeca Film Festival in New York.
They met on the set of "Ondine" and instantly fell in love.
In the movie Farrell is an Irish fisherman who falls for a mermaid, (Bachleda).
Although the couple avoided any display of public affection when they walked the red carpet and attended the after party at Soho's Bebe restaurant there is no questions these two are very much in lurv!!
"We met on the set, and we were very professional and focused on our part and our jobs," said the Mexican-born, Polish actress Bachleda, 26.
"The story itself is so beautiful … we really didn't have time to get our true emotions [on screen]."
Ironically, Farrell said the hardest part of the movie was perfecting a certain Irish dialect for the role. "one of the hardest accents I had to do, because I felt a national obligation not to [muck] it up."
He explained, "Even though Ireland is a small island, there are a plethora of dialects. I was more familiar with the American accent watching T.J. Hooker in CHiPs than I was with the Irish accent in this particular town. It was a very kind of impenetrable accent."
Farrell speaks with a strong Dublin accent.