Continuity mistake: When everybody is at the rehearsal for Grant and Julia's wedding, when Bernie does a toast to Julia and Grant, watch the level of water in Roz's glass, it changes without her even touching it.
Continuity mistake: When Hitch is moving close to Julia to check her breath, he has a tin of Altoids in his right hand. In the next shot, he is not holding the Altoids but reaches into his left pocket and pulls them out.
Revealing mistake: When Julia does her dance for the firemen, they hit her with the fire hose and she gets knocked back. In a few shots after that, especially in the close-up of her swishing her hair back, you can see on her neck that the neck-fat piece has come loose.
Visible crew/equipment: At the beginning of the movie, when Julia is doing her "Milkshake" dance, she goes over and starts dancing to the taxi driver. In the side shot of Julia dancing for him, the camera can be seen reflected in the side of the taxi.
Continuity mistake: In the scene where Juila is running up the stairs to meet up with Grant at her rooftop, her shoes keep changing. In one shot she has slip-ons; in the next shot where she pushes Andy down the stairs, she is wearing tennis shoes. Keeps going back and forth.
Continuity mistake: In the scene with Jinxers and the old neighbour lady are eating strawberries, the plate of strawberries is in front of Jinxers. It cuts to Julia again and back to Jinxers. The strawberries are now to the side on a different plate.
Other mistake: When Julia is trying to pop her zit with a plier, it's obvious she isn't applying any pressure.
Continuity mistake: When they are all at the rehearsal dinner and they are all singing, once we have seen the picture of Julia with the beard and moustache, Grant's Dad puts his fork down and we hear it clink. Then in the next shot he puts a knife and a fork down on his plate.
Continuity mistake: In the beginning when Julia is dancing over the vent, you can see she is wearing black underwear. Later when she is sprayed with the hose and knocked over, she is wearing flowered underwear.
Continuity mistake: When Julia and Grant are at "A Restaurant", watch the necklace on her neck. It keeps moving position throughout the whole restaurant scene.
Factual error: When Julia gets on the motorcycle the engine starts with a turn of the key, and then turns off the kill switch. In real life the motorcycle starts after you turn the key, disengage the kill switch then push the electric start button.