Big Brother 4.1 is the fourth season of the Polish reality television series Big Brother. The show followed a number of contestants, known as housemates, who are isolated from the outside world for an extended period of time in a custom-built house. Each week, one of the housemates is evicted by a public vote, with the last housemate remaining winning a cash prize. The show returned after five years break. It was launched on September 2, 2007 and concluded on December 6, 2007, last 106 days.