'Law and Order SVU' season 18 episode 5 spoilers: 'ER' alum Anthony Edwards plays Benson's first partner in upcoming episode

"ER" co-stars Mariska Hargitay and Anthony Edwards reunite in "Law and Order: SVU" season 18 episode 5NBC

Benson (Mariska Hargitay) will be forced to make an extremely difficult decision when "Law and Order: Special Victims Unit" season 18 returns to the small screen after its short hiatus.

Episode 5 of the season is titled "Rape Interrupted." It will mark the long-awaited "ER" reunion between Hargitay's co-star and onscreen love interest in the medical drama, Anthony Edwards, as they will both appear in this episode.

In "Law and Order: SVU" season 18 episode 5, Edwards will play the role of academy sergeant Patrick Griffin who also happens to be Benson's first partner on the job.

They meet again after the former's son was taken in by Benson's team after sexually assaulting an unconscious woman, which eventually led him to be charged with rape.

The promo for "Law and Order: SVU" season 18 episode 5 appears to show Griffin asking Benson to help his son, holding on to the fact that they go way back.

Benson was hesitant and said that "this isn't going away." However, it looks like she might give in as Barba (Rafael Esparza) notices that her history with Griffin is beginning to cloud her judgment.

This might have something to do with the threat that the sergeant gave Benson in the promo for the upcoming episode.

"You're looking at the fight of your life; you and your whole department," he told Benson as he stormed out. This ultimately forces her to choose between loyalty and duty.

Speaking to E! Online about the reunion and why it took so long, Edwards said that it was a matter of perfect timing. He also revealed a few details about his character's dealings and the situation he puts Benson in when "Law and Order: SVU" season 18 episode 5 comes.

"What's intriguing to me is that you've got people that have to help each other. But there are rules and the line of that keeps moving," the actor said.

"We had a certain relationship then, and now here we are in a situation in which I'm in great need and I'm drawing on this old friendship," he went on to say.

"Law and Order: SVU" season 18 episode 5, "Rape Interrupted," is scheduled to air on Wednesday, Oct. 26, at 9 p.m. ET on NBC.