"Episode 9 I come back," Lahti told TVGuide.com, saying there's definitely "a clash" in one scene with Assistant District Attorney Alex Cabot, played by the recurring Stephanie March.
Lahti said her character, Sonya Paxton, has "some hidden secret demons that are very intense." She adds that her character, who "starts out as a control freak, strong, demanding ADA, turns into a wild ride."
So will either Lahti or March fill the ADA role on SVU permanently? Executive producer Neal Baer says it's all up in the air. "Stephanie is doing 10 shows and then she has other things to do, so at the end of the season, [in] the last five shows, anything could happen."
"I have some ideas," he adds.
Law & Order: SVU premieres Wednesday at 9/8c on NBC.
Who would you cast as ADA?