HBO's In Treatment, that is. Blair Underwood, Melissa George and Dianne Wiest have been added to the cast of Gabriel Byrne's half-hour drama series, based on (no kidding) an Israeli hit. Byrne plays a shrink who's beyond therapy, while Underwood and George play his patients. The fantabulous Wiest, last seen badly miscast on Law & Order, is Byrne's once and future analyst.