You may also know him as Steve from “Sex and the City.” He’s probably one of the coolest, if not the coolest celeb I’ve ever met. Check out my interview with him as we talked about what it’s like filming “Chicago Fire” in our city, what Lady Gaga is like on set with David’s co-star Taylor Kinney (they’re dating) and what it was like playing Steve on “Sex and the City.” Catch “Chicago Fire” every Wednesday night at 9 on NBC!