The 37-year-old actor stars alongside Emma Thompson and Tom Hanks in the movie about how Disney classic Mary Poppins was adapted for the big screen, reported Contactmusic.
Farrell says Thompson's performance as Mary Poppins author P L Travers was so moving that he could not help shedding a tear when he watched a screening of the movie.
"I did too and I'm in it, so how pathetic is that? I think Emma Thompson just rips you from one side of the room to the other emotionally; there's something particularly raw about what she does in this," Farrell said.