The Grey's Anatomy star ''felt a lot of pressure'' shooting last season's shocking finale in which Izzie's boyfriend, Denny, dies. ''He represented her dreams for the future, and she lost it all in seconds,'' says Heigl. ''You don't want it to be melodramatic and schmaltzy. I listened to sad music all day, which influenced me. This is one of the few opportunities I've had to really be challenged.''