Another alum is returning to the Law & Order family.

TV Guide has learned that Sam Waterston is headed to Law & Order: SVU for one episode this season. Waterson, who currently stars on the Netflix series Grace and Frankie, is best known for playing prosecutor Jack McCoy for 16 seasons on Law & Order.

Details surrounding his appearance are scarce but we think it might have something to do with Peter Stone (Philip Winchester), the Chicago Justice alum who is also making his way to the show as an Assistant District Attorney in Season 19. Peter is the son of Ben Stone (Michael Moriarty), ASA on the first four seasons of Law & Order who was then succeeded by McCoy. If you couldn't already tell, the Munchinverse is very small and very connected.

Chicago Justice's Philip Winchester Joins Law & Order: SVU

As we previously reported, the show is also bringing in Brooke Shields for five episodes that will rock Olivia Benson's (Mariska Hargitay) world. "I play a very different character from any I have ever played," she said in a statement. "I'm excited to stir the SVU pot a bit."

Law & Order: SVU returns Wednesday, Sept. 27 at 9/8c. on NBC.