I'm a huge fan of Hawk's His Girl Friday, but my enthusiasm for that film does not carry over to Bringing Up Baby. Hepburn and Grant are both solid but the hijinks, slapstick, and banter between the stars simply does not work here. I actually found Bringing Up Baby to be more irritating than entertaining. Grant and Hepburn have worked together quite well, as in The Philadelphia Story, but I think one of the obstacles to this film is that they haven't yet figured out their timing and rhythm to a degree that they work well together. It will come with time but they still had some kinks to work out at this point.
Review of Bringing Up Baby
