It's time to meet the new boss.

John Larroquette makes his debut on CBS All Access' The Good Fight in this Thursday's episode as Gavin Firth, a controlling lawyer from the STR Laurie conglomerate that recently acquired the struggling Reddick Boseman & Lockhart law firm.

With new overlords watching their every move, Diane Lockhart and company are understandably on edge. So when Lucca Quinn (Cush Jumbo) is summoned upstairs, it's a little... nerve-wracking.

"I'm the sorting hat of lawyers. Do you know what that means?" a bespectacled Gavin asks Lucca Quinn in his expansive, but barren office, in ET's exclusive sneak peek.

"Is it a Harry Potter thing?" an unamused Lucca inquires. And soon, the two engage in small talk about why she's one of the only people in the world who still hasn't read Harry Potter. Her answer? "I don't like... wizard sh*t."

Apparently, that's the correct response because soon enough Gavin expresses his appreciation for Lucca. But a guy of Gavin's stature doesn't just become fast friends with someone without wanting something in return. And sure enough, he wants something in return.

A high-priority divorce case is proving problematic for STR Laurie because of a personality clash between the divorce lawyer on the case and the client. Lucca's assignment is to work with the attorney to "smooth out the sharper edges" -- only she's all to familiar with the "problematic" attorney: none other than David Lee (Zach Grenier). 

This is going to be interesting. Watch ET's exclusive clip above to see what happens next.

Recently, ET spoke with The Good Fight star Sarah Steele, who plays investigator Marissa Gold, who talked about the show embracing its zaniness in season four.

"We started to get very zany in season three, which I love. I think season four keeps that up without ever crossing into it being too much. What I like about it is this whole corporate takeover of the firm... the drama that you can have between the characters, you almost go through everything that can happen and then you need the whole world to be upended," Steele said. "That's what we've done this season on The Good Fight. They blew up the world they built. Now, it's this other thing where the whole firm is an underdog and the dynamics that used to exist between the people in the firm are now existing on this other plane because our bosses now have bosses."

The Good Fight drops new episodes every Thursday on CBS All Access.

To stay up to date on breaking TV news, sign up for ET's daily newsletter.