Factual error: When Debra Messing and Dermot Mulroney 1st arrive in London Debra goes to a pub to change her outfit, the shot showing the outside of the pub you can see an American style traffic lights eg walk, don't walk which are nothing like the English green man red man traffic lights.
Continuity mistake: When Dermot is drying off in the bathroom, he is holding the towel in his left hand and by his side, but in the shot of Debra he is holding the towel at his chest. Then cut back to Dermot and he is holding it by his side again.
Continuity mistake: In the scene where Debra Messing and Dermot Mulroney first arrive in London at the first party, Debra's jacket belt is undone when they enter through the door, then done up tightly when they are shot from a different angle, and undone again as those move from the room.
Continuity mistake: During the "shower scene" when Dermot comes out naked and Debra looks away with her hand on her mouth, her hands keeps changing places. Facing her, she puts her hand on her mouth, but in a side shot, she has her hand over her eyes. Then when facing her, she has her hand over her mouth again.
Continuity mistake: When Debra and Dermot get to the big house and go into the room with the big bed, Debra walks into the room and her dress is hanging off one shoulder. Then when the back shot, her dress is off both shoulders.
Continuity mistake: Just prior to the wedding (near the end), when Debra and Dermot are outside the church standing beneath the arbor, she is holding her floral bouquet. When they enter the church, the bouquet is gone; Once she's walking down the aisle, the bouquet reappears.
Continuity mistake: When they are going to bed for the first night and Debra is putting pillows between the two of them, a pillow near both of their heads changes. In one shot, it has lavender ribbons. In the next shot there are no ribbons and it's a different color.
Continuity mistake: When they are at the park playing a game of rounders (similar to baseball or softball), Kat pours water down her throat, and it runs down to her pants. In one shot it's wet, and in the immediate following shot, it's dry.
Continuity mistake: When Nick is showing Kat how he kisses women the sun changes between shots.
Continuity mistake: The dance lessons take place the morning after stags and hens, making it Friday. But they're suppose to be two days before the wedding, so they should have been before stags and hens on Thursday. When Kat arrives at the cocktail party, from the airport, her mother gives them the itinerary. Tomorrow is young people in the park, followed by stags and hens, Friday is the picnic, then the rehearsal dinner. During the party, she's talking to her sister at the bar, after a stumble with the fiancee, Amy says they have dance lessons two days before the wedding.
Factual error: Kat goes to multiple ATMs to withdraw money, since the limit on machines in the UK at the time was £250. However, that limit is for withdrawals from one account in one day, not from individual ATM machines. You can take as much as you want from your accounts in person at the bank, but not from machines. It's ridiculous to think she would've had enough different accounts to only take £250 from each but return with thousands.
Continuity mistake: At the wedding dance the sun is changing in every shot.
Continuity mistake: At the game when Kat is batting, the guy behind her in a red shirt moves away between shots.
Factual error: When they are leaving the USA to fly to London and are checking in at the airport, a guy walks past in an Easyjet ground handler's uniform. Easyjet doesn't operate in the USA - clearly filmed in London Gatwick airport.
