吉伦哈尔在本片里的造型可谓让人大跌眼镜，饰演一位报道犯罪事件的记者，常常出没于黑暗的地下世界，与各种边缘人物打交道，因此他希望自己的形象能体现角色“心理上与身体上的饥饿感”。昔日的帅哥为拍摄这部《夜行者》狂减18斤(20磅)，脸颊凹陷甚至神似瘾君子。吉伦哈尔在新片中当问及减肥的方法，吉伦哈尔表示：“我只是非常热爱这部电影，除此之外没有什么窍门。” Gyllenhaal modeling in this piece may let teeters on the National People's Congress, playing a reported crime reporter, often lurking in the dark underground, dealing with a variety of edge character, so he wants his image can reflect the character of "psychological and physical hunger sense." The old guy for filming the "Night Stalker" mad minus 18 pounds (20 pounds), even in addicts with sunken cheeks. Gyllenhaal in the new film when asked about weight loss method, Gyllenhaal said: "I just love this film, in addition to no tips."