Joaquin Phoenix attends the "Joker" premiere during the 2019 Toronto International Film Festival at Roy Thomson Hall on Sept. 9, 2019, in Toronto. (CNN) - Joaquin Phoenix is known for being extremely private and rarely mentions his late brother, River. Phoenix thanked his late brother during an emotional acceptance speech Monday at the Toronto International Film Festival after he was awarded the TIFF Tribute Actor Award. The Phoenix brothers aren't the only ones who have found success in Hollywood, as their sisters Rain, Liberty and Summer are also actors. Joaquin Phoenix also had words of gratitude for them Monday in his speech.