Towards the beginning of the movie, after Thomas Crowne has identified the man he tripped, he is being couseled by the detectives about testifying. Catherine goes to get herself a coffee. She most obviously takes a cup off the top of the coffee machine that is white with green and purple swirls - just like the rest of the cups on top of the coffee maker. You get a good look at the cup when she lets go of it to put milk in it.

Seconds later, during the same scene, the next time the camera shows Catherine, she is looking out the window watching Thomas Crowne run to his Mercedes, but she is sipping out of a completely different cup. Her new cup is white and blue with a greek theme to it.