The 62-year-old actor will play Dr. Cap Jackson, a sex therapist who runs a sex addiction rehab clinic. The episode, titled "Mask," is scheduled to air in early 2011.
"We're elated to work with an actor of Jeremy's caliber," executive producer Neal Baer says. "He brings depth, intelligence and charisma to all his varied roles and we couldn't be luckier to have him guest-star on SVU."
Irons won an Academy Award and a Golden Globe in 1990 for his role in Reversal of Fortune. He won another Globe as well as an Emmy and Screen Actors Guild Award for his 2005 performance in HBO's mini-series Elizabeth I.
Irons is also set to star in the upcoming Showtime period drama, The Borgias. Irons plays Rodrigo Borgia, the patriarch of a corrupt, Renaissance-era Italian noble family who becomes Pope Alexander.
Law & Order: SVU airs Wednesdays at 10/9c on NBC.