The Law & Order Star You Likely Missed On ER

The "Law & Order: Special Victims Unit" star that shares a past on "ER" with Mariska Hargitay is none other than Donal Logue. 

The actor was, of course, revered as one of Hollywood's most prominent "That guy!" types (per Rolling Stone) long before joining the cast of "Special Victims Unit" in 2014 as NYPD undercover specialist Lt. Declan Murphy. That status has only continued to grow with every appearance since. The most recent Declan Murphy sighting came in a Season 23 episode that reveals he's no longer working undercover, and instead heading up the NYPD's Hate Crimes division. It's also revealed Murphy is indeed the father of Det. Amanda Rollins' (Kelli Giddish) daughter, so we'd be very surprised if he doesn't make his way back into the "Special Victims Unit" fold somewhere down the road.

As for Logue's "ER" role, it was also in a recurring capacity, and it came much earlier in the actor's career. In fact, his first appearance as flight nurse Chuck Martin came in 2003. It initially added a touch of light-heartedness to the show too as Chuck was revealed to be the husband of Dr. Susan Lewis (Sherry Stringfield), whom she'd impulsively married on a trip to Las Vegas. The marriage was ultimately annulled, but the pair kept their relationship going and eventually had a child together. Logue's time on the show ended late in Season 11, but the role remains arguably one of the best from his pre-"Special Victims Unit" days.