(NBC) — NBC’s “Law & Order” universe welcomed Maura Tierney into the fold last fall on the original, “mothership” series.

On Thursday, Tierney will experience her first crossover event. Tierney and “SUV” mainstay, Mariska Hargitay, discussed the developing connection between the actresses and their characters.

Their characters had a rough first meeting, but for Tierney and Hargitay, their first “Law & Order” encounter was different.

“She came to set my very first day, which was so nice and welcoming,” said Tierney.

“I said, ‘I have to go by and welcome her, welcome her to the family,’” said Hargitay

The initial friction between their characters, Benson and Brady, gives way in Thursday’s crossover event.

“They’re very different people, but I do believe they’re two sides of the same coin,” said Hargitay.

“They just go at it differently, their approach is different,” said Tierney.

They form a united front in tackling a cold case.

Hugh Dancy, who plays Assistant District Attorney Nolan Price on “Law & Order,” revealed where the real tension will appear in the episode.

“The conflict is more, if anything, between Brady and Benson’s kind of, ‘Let’s go, let’s do this,’ and us [Price and Assistant District Attorney Dominick Carisi, Jr.] saying, ‘That’s all very well, but we gotta slow down and do it the right way,’” said Dancy.

“[Hargitay] goes, ‘This scene’s about the girls versus the boys,’” said Tierney.

The bond between the female characters is catching up to the one between the veteran actresses.

“I don’t love talking about age so much, but there’s a lot we can bring to each other in terms of how long we’ve been doing this,” said Tierney.

“With her, I feel relaxed because I trust what will be,” said Hargitay. “That is a gift. That is a real gift.”

Just like the crossover event.

Watch Thursday’s “Law & Order” crossover event at 8 p.m. on NBC4.