Chennai Express is doing brisk business not only in North India, but at the southern box office and in international markets as well. The romantic comedy`s lead actor Shah Rukh Khan feels it`s a good sign for the Indian film market. "It`s a good sign not only for us, but for the films that came and that will come in the next five-six months... the market of Indian films is so big," Shah Rukh told reporters Thursday at the INOX theatre, where he came with the film`s director Rohit Shetty and interacted with media and fans. Also starring Deepika Padukone, the movie is a co-production by Shah Rukh`s Red Chillies Entertainment and UTV Motion Pictures.