Farrell became a father for the second time when his girlfriend, Polish actress Alicja Bachleda, gave birth on October 7 in Los Angeles, reports People.
However, the news has been kept quiet since the birth, and was only confirmed on Friday (October 30) by a spokesperson for the Irish star.
The baby has been named Henry Tadeusz Farrell, and he is the first child for the 26-year-old actress. Farrell, 33, has a six-year-old son, James, from his relationship with model Kim Bordenave.
Last September at the Toronto International Film Festival, Farrell confirmed that his girlfriend was pregnant. "I will take it as it comes. Even changing dirty diapers," joked the star.