“Ugly Betty” (8 p.m., ABC): On “Ugly Betty,” an increasingly delusional

“Ugly Betty” (8 p.m., ABC): On “Ugly Betty,” an increasingly delusional Renee (Gabrielle Union) becomes convinced that Betty is in love with Daniel, so she feels the need to become her rival. Also, Nina Garcia and Christian Siriano of “Project Runway” drop by, playing themselves.

“Grey’s Anatomy” (9 p.m., ABC): Look who’s back on “Grey’s Anatomy.” Addison (Kate Walsh) returns for one episode to perform a special operation and is stunned by all the changes that have happened at Seattle Grace. Meanwhile, Rebecca/Ava returns with shocking news for Alex.