Law & Order Casts Ryan Eggold as [Spoiler]’s Brother, Mariska Hargitay and Elizabeth Marvel to Guest-Star

For his first TV appearance since New Amsterdam wrapped its five-season run, Ryan Eggold is set to guest-star on another NBC drama — Law & Order .

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Law & Order: SVU front woman Mariska Hargitay and franchise vet Elizabeth Marvel are also lined up to appear on the original series’ revival this fall.

Eggold, TVLine has learned, will guest-star in a Season 24 episode of Law & Order as Matt Riley, the brother of Det. Vince Riley (played by Veep vet Reid Scott, who joined the cast last season).

Prior to Eggold’s appearance, Hargitay will cross over Captain Olivia Benson in an October Law & Order episode, with Marvel reprising her SVU role of Defense Attorney Rita Calhoun during the same hour.

Marvel has played Calhoun in more than a dozen SVU episodes, spanning March 2010 through January 2021. (She also played Defense Attorney Grubman in a pair of late-aughts L&O episodes). The actress was most recently seen on Apple TV’s Presumed Innocent , as former District Attorney Raymond Horgan’s wife Lorraine.

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Law & Order , as previously reported, is undergoing another significant cast change this season. ER alum Maura Tierney has joined the Season 24 cast in the series regular role of a new lieutenant, filling the void left by original revival cast member Camryn Manheim’s exit as L. Dixon .

Over on SVU , meanwhile, Kevin Kane has been promoted to series regular for Season 24, as Det. Bruno.

Law & Order Season 24 kicks off Thursday, Oct. 3 at 8/7c, where it will be followed by SVU Season 26.

Want scoop on any Law & Order series, or for any other TV show ? Email InsideLine@tvline.com , and your question may be answered via Matt’s Inside Line!

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