Peter Scanavino Teases ‘Real Mind-Blowing’ ‘Law & Order’ Crossover

It’s a big week in the “Law & Order” universe, as the mothership will cross over with “SVU,” but it’s also a big week, personally, for Peter Scanavino.

“It did feel kind of like an achievement for not just my character, but also for myself,” Scanavino tells TODAY.com, “and, you know, kind of growing up on original ‘Law & Order.’ I’d been in it as a guest star, but to be in it as this character, it felt great.”

The actor portrays ADA Dominick “Sonny” Carisi on “Law & Order: Special Victims Unit” and previously had guest roles as other characters on both “Law & Order” and “SVU” before landing full time as Carisi, who started out as a cop before transitioning to the legal side.

He says he never imagined he would be in this role for over 10 years now.

“But I’m certainly glad that I am … I’m very grateful to have been on this show, which has changed my life completely,” he says.

He explains his character becoming a lawyer “coincided” with the return of Warren Leight as “SVU” showrunner. Leight led the show from Seasons 13-17 and later returned for Seasons 21-23.

“Warren Leight created my character, and one of the character details that he put in, and it’s in the first episode, was that my character was going to night school at Fordham Law — that he had aspirations to be a lawyer,” Scanavino says about Carisi, who’s also this “blue-collar kid from Staten Island” with “ambition” to pursue the rules of law.

Scanavino says when Leight came back for Season 21, the showrunner approached him with the idea of Detective Carisi’s career change.

“Honestly, the parts I had always loved about ‘Law & Order’ the most, when I would watch it, were the trial scenes,” he says, explaining it has been “quite a journey” for Carisi.

“When I became the ADA, it was starting from scratch,” he says. “Usually, you would see the attorneys or the ADAs are more polished. They’re already at the peak of their career, and I really had to have some runway to get there.”

Five seasons later, Carisi (and Scanavino) is getting his chance to shine with the “Law & Order” legal powerhouses, which include ADA Samantha Maroun (Odelya Halevi) and EADA Nolan Price (Hugh Dancy), and their boss, DA Nicholas Baxter (Tony Goldwyn).

The crossover will air Thursday, April 17, starting at 8 p.m. ET on “Law & Order” and continuing at 9 p.m. on “SVU” on NBC.

Scanavino explains the case comes from the pasts of both Maura Tierney’s and Mariska Hargitay’s characters. Tierney joined the mothership this season as Lt. Jessica Brady, and Hargitay has played Olivia Benson, currently captain of the Special Victims Unit, on “SVU” since the show debuted in 1999.

“They have personal stakes in the crime,” Scanavino explains, “and then it moves forward through the legal system.”

In the two-part crossover, “Play with Fire,” Benson’s team responds to the scene of a brutal murder after she receives a mysterious phone call. The squad teams up with Brady’s crew to investigate a pattern of rape and murder targeting marginalized women.

An April 10 promo offered more insight, implying the victim is Maria Recinos, a police officer who joined the department last year. Benson has a history with Maria and saved her as a young girl in the Season Seven episode “911,” which also won Hargitay an Emmy Award.

Carisi works with Price to see if they’re able to prosecute the case and if they have enough evidence even though, Scanavino says, “it becomes somewhat obvious as to who’s responsible” for the crime “through several twists and turns.”

He also teases “very good courtroom stuff” combined with “a lot of great detective work.”

“Everyone working together,” he adds. “It’s a true crossover in that it’s not just a couple scenes here and there. It’s a two-hour event.”

Scanavino, who told TODAY.com last year he would “love to cross over into that world” on the mothership, says the experience visiting the set and collaborating with those actors was “really cool.”

“I almost felt like I was an animal that had been raised with a different species of animal, and then I came home to the den for the first time,” he says while laughing, “because they had this really nice legal set, and the district attorney’s offices, and there were all these lawyer extras zooming around. We don’t really have that on our show. So I felt, ‘Oh my goodness, look at this whole other world! I’m a lawyer, and so are these people.’”

He adds it was “awesome” working with Dancy and Goldwyn and visiting their “beautiful” set.

Scanavino says his favorite part of the experience happens when the team is not filming and “just busting chops and joking around in between takes.”

“Everyone there is very funny. Hugh is very funny, Tony is very funny, Maura is very funny,” he says before laughing. “You put Mariska into it, who’s hilarious, and everyone is really kind of like a bunch of unruly third graders. And the directors are like, ‘Everyone! Please focus.’ So those are the best parts.”

As for how his character gels with Dancy’s, Scanavino says while they have different styles, they “get along very well.”

“I get a sense in the crossover Carisi is kind of more headstrong in terms of prosecuting, and Price is more kind of, ‘OK, let’s slow down. Let’s make sure we can go in with the amount of evidence that we need.’”

“There’s not a lot of animosity,” he adds. “It seems a mutual respect.”

Someone else Carisi has mutual respect for is his wife, Amanda Rollins (Kelli Giddish). Giddish has made a few guest appearances so far in Season 26.

“I have a feeling that you will see Rollins again,” Scanavino says, adding, “What a gift that is considering that Kelli Giddish is such an amazing actress and person.”

Until then, Scanavino is excited for fans to see what goes down this week.

“I think if you’re a fan of either show, you’re going to really love this,” he says about the crossover. “And if you love both shows, this is going to be a real mind-blowing event.”

The “Law & Order” crossover event begins Thursday, April 17, at 8 p.m. on NBC.