Hargitay uploaded a black and white, behind-the-scenes photo of herself and Meloni in front of a cemetery.
The actress also released a photo of their chairs, which feature their character names Stabler (Meloni) and Benson (Hargitay).
"It's all happening... #OC #PFL," Hargitay captioned the image.
Hargitay's Olivia Benson and Meloni's Elliot Stabler will briefly join forces again in Law & Order: Organized Crime, after the pair appeared together for 12 seasons on Law & Order: SVU.
Organized Crime is a spinoff of SVU that will follow Stabler as he returns to the NYPD to battle organized crime following a devastating personal loss. It will premiere in spring 2021.
Hargitay teased reuniting with Meloni in July.