Continuity mistake: While Alex is doing his striptease dance, you can see a girl wearing a white shirt in the crowd behind him. She moves around during the scene, sometimes not even being visible at all.
Continuity mistake: When Courtney takes the knife off Michael that he is using to ice the cake, the close up shows her taking some cream off the knife with the finger that is on her left hand but when she puts it up to her mouth the cream and the knife has switched hands and also there is twice as much cream on the knife.
Continuity mistake: When Michael drops Courtney off at her house, she gets off the motorbike twice.
Continuity mistake: When Alex storms into Michael's apartment to yell at him about Maria, Michael closes the door behind him. Then, only seconds later, the door is wide open just before Alex punches Michael.
Continuity mistake: When Tess pulled the plug out of Courtney's bath, the plug was out for quite a while but the water hardly went down.
Continuity mistake: In the scene where Kyle and Tess are sitting on her bed and talking, she leans forward and hugs him by putting her arms around his neck. The shot then changes to his face and her arms are around the tops of his shoulders. When the shot changes back to her face again, her arms are around his neck again.
Answer: It's called "Here With Me", performed by Dido. It can be found on her album "No Angel".
Tailkinker ★