As season five of The Good Wife begins tonight (May 29) on RTÉ One, Josh Charles talks to John Byrne about the massively successful show, working with Jullianna Margulies, and how he’s developed as an actor.

You can hype up Breaking Bad and Game of Thrones all you like, but The Good Wife is - by some distance - the best mainstream show on TV these days.

Sure, when you’re cable, particularly HBO, there’s a cool cachet that goes with the bonus of being able to go X-rated to a level that just wouldn't be acceptable on a traditional US network such as CBS, which is home to The Good Wife. So you gotta work harder in other ways to get noticed. This is TV for grown-ups.

What The Good Wife does in spades is tell compelling stories about interesting characters, using an extraordinarily-talented ensemble cast and probably the greatest collection of guest stars ever assembled on telly.

Much more than a straightforward legal drama, it's is also a tale of intertwining personalities and interests, loves won, lost and unresolved, and some of the greatest, attention-grabbing opening scenes in TV history.

Did I mention that I'm a fan?

Leading the charge on many levels is Josh Charles, the intense 42-year-old American actor who plays the pivotal role of Will Gardner. As well as being a key partner in Lockhart-Gardner, the show’s legal firm, he’s the former boyfriend of Julianna Margulies’ character, Alicia Florrick, the eponymous Good Wife.

But you know that, don’t you? If not, you've already missed four fantastic seasons. With the fifth starting Thursday May 29 on RTÉ One, you've a bit of catching-up to do. Lucky you.

For fans of the show, well – what can I say? What can Josh Charles say ahead of this sensational fifth season which I refuse to ruin here with spoilers? [If you know what's coming - do everyone else a favour and keep it to yourself.] Ask him about The Good Wife and the secret of its success and he rattles away like Beyonce delivering one of her trademark scattergun melodies.

“I think it’s well-done television,” he says. “It’s timely,” he adds. “I think the writers do a great job of working in storylines that are interesting and informative but not preachy or pretentious.”

He takes a breather. He’s only getting started.

“I think the show is dramatic and at times satirical,” he adds, before hitting a roll. “I think it combines different tones in a very good way and it never loses sight of its being there to entertain which I think is a very good driving force behind the show and leads to it not being pretentious which is what I appreciate about it.

“So I think there’s many reasons [why The Good Wife is successful],” he concludes, closing his case with Will Gardner-like certainty.

Charles first gained prominence as a teenager, playing the impulsive Knox Overstreet in the 1989 movie, Dead Poets Society. In more recent times he was jaw-droppingly intense as Jake in the first season of In Treatment, playing a superb three-hander with Gabriel Byrne and Embeth Davidtz.

In short, he’s been doing this acting thing very well for some time.

Just one glance at the guy playing a role and you know he takes his thespian tasks very seriously. So how does he feel he’s developed as an actor?

While initially responding with “That’s a good question,” he carries on to answer in a way that suggests he has a more emotional than cerebral approach to his craft. “I don’t know actually how I've changed as an actor but I think, I think you’re always changing as an actor.

"I mean I think that’s one of the beauties of acting. It’s a profession, like many others, that you could just keep growing in and deepening and trying to get better and better.

“And I think what the, what the sort of rigours of a television schedule force you to do is, you know, learn material very quickly and turn it around very quickly and get it on its feet.”

Acting can be quite a lonely furrow, what with the arbitrary and transitory nature of the industry, but there remains a great respect amongst those involved at all levels and The Good Wife is no exception, both in terms of characters and those who play them.

When it comes to Alicia Florrick he feels that there are “so many things to admire. But I think her strength, her sort of, her dignity, her morality that - certainly as the shows progressed - has gotten tested and tested again.

“I think I would say that or her innate dignity, grace and goodness to do the right thing and to, and to be a good parent and to try and be a good wife as much as she could. I think all those things that she sort of leads in a very good, positive way.

“But she’s also a very complicated human being,” he notes, almost Will-like. “And I think that makes her more interesting. And I like her for her flaws too. So there’s a lot. There’s a lot. I think she’s a wonderful character played by a wonderful actor so that combination is fantastic to watch.”

So let’s leave Josh Charles with the last word on the star of the show, Julianna Margulies.

“Julianna can do so much without, you know, saying anything,” he feels. “I always tell her that I thought she would have been the most incredible silent film actress because sometimes those acting with her and then, you know, watching her direct just does so much with a look, with her eyes.

“I'm envious, you know,” he adds, half-playfully and completely in earnest. “She can really do it and just so effortlessly. And it’s fun to watch. And she’s also, you know . . . I love the comedy in her too. I mean Alicia makes me laugh sometimes too. She’s very funny.”

The Good Wife is on Thursdays on RTÉ One

Here's the season five trailer/teaser: