EXCLUSIVE: 'Good Fight' Star Justin Bartha Teases 'Intense' Romance With Colin and Lucca -- Watch Sneak Peek!

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Justin Bartha
is just getting started on The Good Fight.

The 38-year-old actor made his debut on The Good Wife spinoff in last week’s episode, facing off against Diane Lockhart (Christine Baranski) and Lucca Quinn (Cush Jumbo) in the courtroom as Assistant U.S. Attorney Colin Morrello, a rising star in the Chicago law (and dating) scene. One of the city’s most eligible bachelors, Colin takes an immediate liking to Lucca -- and so begins their rollercoaster romance.

“There will definitely be some ups and downs, but the relationship is played very realistically and you’ll find out a lot about both characters through how they deal with this pretty quick and intense relationship,” Bartha tells ET.

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In an exclusive sneak peek from the next episode, premiering Sunday on CBS All Access, Colin and Lucca meet at a local Chicago bar and the two flirt over drinks, before he’s shut down after he asks if she wants to go home with him.

“We’ve really gotten into a groove of really showing how difficult it is to have a passionate relationship while also being incredibly career-driven and having conflicts when the two worlds collide,” Bartha says. The upcoming installment features the return of Matthew Perry’s Mike Kresteva, whose agenda against Diane and Lucca’s firm -- and thus how Colin is roped in -- becomes known in Sunday’s episode.

“Because Colin and Lucca are in the same world, they can use each other in positive and negative ways,” Bartha says. “Once you open that Pandora’s Box of using your significant other for professional purposes, the lines can blur to what is the truth and what is ambition. They’re both incredibly ambitious characters and people. It’s a fresh take on a relationship within The Good Fight universe.”

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Asked if he viewed Colin and Lucca’s relationship as being similar to that of Will (Josh Charles) and Alicia (Julianna Margulies) on The Good Wife, Bartha admits he hasn’t fully caught up on the mothership series but knows enough to insist this pairing is “different.”

“Colin and Lucca get into a relationship pretty quickly. We’re not going to beat around the bush; it’s not a ‘will they, won’t they’ kind of thing. It’s a more passionate version of [Will and Alicia],” Bartha previews. “Once Colin and Lucca fall, they fall hard, and then they have to clean up the pieces of their professional lives as it gets in the way.”

A new episode of The Good Fight premieres Sunday at 12 a.m. PT/3 a.m. ET on CBS All Access.

For more on The Good Wife spinoff, watch the video below.

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