John Slattery Could've Played One of Law & Order: SVU Biggest Characters

He's also been a semi-regular of the Marvel Cinematic Universe as Howard Stark — the late father of Edward Stark, aka Iron Man (Robert Downey Jr. ), who still appears on the screen thanks to flashbacks and time travel.

As you can see, John Slattery is an accomplished actor, but not exactly an A-list star. So he might regret not getting a potentially career-changing role back in the late 1990s. That role was on NBC's police procedural Law & Order: Special Victims Unit, currently the longest-running scripted live-action series on American TV.

But can you guess whom John Slattery was supposed to play on that series?

For much of SVU's seemingly endless run, its main characters were the Detective duo of Olivia Benson (Mariska Hargitay ) and Eliot Stabler (Christopher Meloni), and needless to say, they ended up as some of the most beloved crimefighters on the screen. But recently we've learned that this duo might have been very different, because John Slattery was in the running to play Stabler.

Hargitay and Meloni said as much straight up when they've recently appeared on Late Night with Seth Meyers. They not only promoted their shows, both SVU and the new Law & Order spin-off, Law & Order: Organized Crime, in which Meloni stars. They also ended up hilariously re-enacting their first meeting.

As it happened, in that moment, Hargitay actually mistook her future co-star for John Slattery, with whom she was also scheduled to screen test. She did not say if Slattery actually turned up for that screen test, but it seems he at the very least advanced far enough down the casting process that a read with Hargitay was in the plans.

But in the end, Slattery was not fated to get a main role on Law & Order: SVU. And while he's a good actor by any measure, the results speak louder than words – SVU's casting team clearly made the right call.