Actor Nikitin Dheer says his "Chennai Express" character Tangaballi challenged him to perform better in front of superstar Shah Rukh Khan.He is thankful to filmmaker Rohit Shetty for giving him a negative character to play."Tangaballi is a character that challenged me to perform better in front of an extremely talented actor; Shah Rukh Khan. He is extremely warm and motivating, that you yourself want to perform better," Nikitin said in a statement. "For that matter, even director Rohit Shetty said that the character was the negative lead because he was pitted against the hero. That was extremely heartening and I am glad I got that opportunity," added the actor, who essays role of Veer Pratap Chauhan in Star Plus show "Ishqbaaaz". "Chennai Express" tells the story of a north Indian man (essayed by Shah Rukh), who falls in love with a Tamil girl, essayed by his "Om Shanti Om" co-star Deepika Padukone. Talking about his stint as Veer Pratap Singh, Nikitin said: "The audience response has been phenomenal and I am really thankful to them to have accepted me as Veer in their favourite show. It's a negative role with a twist and I am loving every bit of playing this character."