Tonight's episode of Suits sees Patrick J. Adams return to the show as attorney Mike Ross for the final season of the USA legal drama. Expecting to face his old mentor Harvey Specter (Gabriel Macht) on a new case, he discovers he will actually be going up against Katherine's character Samantha Wheeler.

Katherine Heigl

"Mike is the protege, Samantha is very competitive. She's heard a lot about this kid and she already knows so much about him that I think him coming on to the scene, it's absolutely her No. 1 goal to knock him down a few pegs," Heigl said of Mike and Samantha's dynamic during a June set visit.

"I worked with [Patrick] and Gabriel yesterday. I got to bear witness, like a fly on the wall, to their dynamic, their friendship, their easy rapport, the wit between them, and go, 'See, that's where all that on-camera magic comes from,'" she praised. "These two guys have this great chemistry, have this fun relationship and that's what created Mike and Harvey."

Check out Samantha confronting Harvey over keeping Mike's surprise return to Manhattan from her.

Working with Adams for an episode in the final season was satisfying for Katherine who was a big fan of the show before joining the cast.

"It's been awesome. I remember the table read, he was calling in because he was still in California with his family and I didn't get to meet him in person yet, but I was on the phone going, 'I can't wait to meet you! This is going to be so exciting! I stepped in when a big part of the show shifted and changed and some of those beloved characters were no longer here, [Gina Torres], Patrick and Meghan [Markle]. It was like missing the boat just by that much, but still getting the great ride because everybody else that I love so much is here. It was wonderful."

While Mike and Samantha don’t immediately hit it off, it was the opposite for the actors who play them. "She was just lovely," says Adams of working with Heigl for the first time. "Our first scene was in my old apartment. We tore through it. It was really, really fast. We laughed a lot, and that was it. It’s really nice to have someone new here because it changes the energy. It’s all the same stuff that I enjoy but with a new flavor."

Suits airs tonight at 9 p.m. ET/PT and 8 p.m CT on USA Network.