Irish film star Jessie Buckley is having a breakthrough year with her star turns in "Wild Rose" and the Emmy award-winning disaster show "Chernobyl."

But this week she returns as a buttoned-down personal assistant to the living legend that was Judy Garland in "Judy." 

Renee Zellweger gives the greatest performance of her career as the troubled starlet, but like every major award-winning performance she doesn't do it alone.

Irish actress Jessie Buckley, 29, is equally outstanding as her no-nonsense, buttoned-down English personal assistant Rosalyn Wilder (the real-life woman whom Buckley got to know prior to her screen performance).

Only Irish people will understand the challenge of playing such an uptight English rose when it's so foreign to most of our natures. But if there's one thing Buckley has already proved it's that she has amazing range.

This year alone she's played a Scottish country and western singer, a Russian wife who watches the horrific radiation poisoning of her fireman husband and now this almost painfully put together personal assistant.

“Yeah, tell me about that,” Buckley tells IrishCentral with a laugh.

“I got to meet the real Rosalyn Wilder and spend some time with her and you know I have been spending a lot of time in England as well. It's just a different kind of emotional energy and rhythm. It's critical to appreciate all that because we're completely different. We Irish, you know, we tend to wear our feelings on our sleeves.”

Buckley, originally from Killarney in County Kerry, says she likes to find roles that are the complete opposite of where she's just been (for proof, she had just shot Wild Rose before moving on to Judy).

“It couldn't have been more opposite ends of the spectrum from me in terms of how someone, you know, lives or expresses themselves. But I love the different qualities each character has and I always feel like I can learn from them. They each kind of leave a little mark on my heart and it makes me look at the world differently because of how they deal with the world differently.”

Judy Garland certainly left her own mark. She's so famous that her ruby slippers from "The Wizard of Oz" are now housed in the Smithsonian Museum in Washington (as is her famous blue and white gingham dress) so in her own way, she's become as iconic as Mickey Mouse or Coca Cola.

Renee Zellweger stars as Judy Garland in Judy

Renee Zellweger stars as Judy Garland in Judy

When you think of Garland nowadays two images probably come to your mind, how she looked in her MGM heyday and how she looked in her later and rather more tragic final chapter, often strung out on pain killers or booze whilst living between grand hotels and continents.

“I think she was just a very fragile force, you know?” says Buckley.

“I think that's kind of what drew me to Judy in the first place because my own character was completely the opposite to who I am in every ounce of myself. I mean, as an Irish person and as you know yourself I kind of wear my emotion completely on the outside of my skin flying around in the wind, whereas this woman Rosalyn, she was buttoned down to within an inch of her life.”

2019 is Jessie Buckley's breakout year

2019 is Jessie Buckley's breakout year

The real-life pair were about as different as could be, of course. Garland was famously needy and unpredictable but Wilder was a straight arrow who wouldn't stand for any nonsense, so they locked horns from their first meeting in real life and now in the film. Onscreen Buckley as Wilder literally shoves Garland onstage at one point.

Tackling the role is the acting challenge of a lifetime for Zellweger. These are big ruby slippers to fill and by the close of her life, Garland was almost a deified figure among her fans. Was that kind of awareness intimidating?

“Oh for Renee I don't think it was. Like I remember when she was doing Somewhere Over The Rainbow. I mean she would just kind of go to the makeup room in the morning with her little cap on and sit in the chair until over the course of an hour she would come out and and be Judy. You couldn't even see the line between the two people you know?”

Jessie Buckley and Julie Walters in Wild Rose

Jessie Buckley and Julie Walters in Wild Rose

Buckley says she would often see Zellweger chatting away happily to the crew members or the extras before she'd stand up and give an incredible performance in front of the cameras.

“Then she'd just step off the stage and chat away to be extras again. She's just that kind of talent, that kind of soul, it was so inspiring to get to watch a woman like her effortlessly and passionately tell a story like that and I just wish her everything in the world. I think she's just the most beautiful creature.”

One thing that never changed throughout Garland's tempestuous life was the adoration of her core fans, many of them gay men, who stuck with her through every peak and valley of her career. In her struggles, they often saw some of their own and it's said that the Stonewall Riots really took off because the oppressed gay community in New York were still reeling over her premature death (her status as a gay icon is deftly noted in the film) and in no mood for another raid.

Jessie Buckley stars as Rose-Lynn in Wild Rose

Jessie Buckley stars as Rose-Lynn in Wild Rose

Meanwhile, Buckley's own career is taking off now too. Does it help to be Irish in Hollywood? Does it prevent her from the worst sin in the Irish catechism, getting notions?

“I don't really think about it, to be honest,” she laughs. “Like I am who I am and I don't think I'm entitled to anything in my life. Wherever I'm from I think you just have to try and be a good person and a good listener and keep being curious about yourself and trying to test the limits of what you don't know about yourself. And have fun, you know.

“I feel incredibly lucky and honestly I'm as shocked as anybody else that somehow I'm doing films in LA. I'm always laughing at myself going Jesus this is crazy, where did I came from? But I really love and care about what I do and I don't want to ever take that for granted.”

The core of Judy is a portrait of a gifted outsider who appealed to follow outsiders. It's also about the star system abused her and the fallout she contended with. “I suppose what she represents is a kind of hope,” says Buckley.

“That even within the midst of being studio property or exploited within an inch of her life by an industry who abused a very precious, delicate pearl of talent, she still managed to hold onto the beacon of hope and her own self. I don't know how she did that, you know, I don't know.”

Jessie Buckley stars as Rose-Lynn in Wild Rose

Jessie Buckley stars as Rose-Lynn in Wild Rose

“It's a precious, precious, rare thing. When you get somebody like that who manages to even to their detriment, to give you every ounce of their heart in the hope they will get something back. And the film shows you that.”

Next up she's playing the famine queen, Victoria, opposite Robert Downey Jr. Can she tell me a bit about The Voyage Of Doctor Doolittle? “Well, I'm the queen obviously. Obvious casting for an Irish person. I don't know how much I'm allowed to say about it. Apart from who I'm playing!”

After that Buckley will film "Fargo" opposite Ben Whishaw here in the U.S. “Well we haven't started shooting yet, but I mean I've just loved him forever, so I'm really looking forward to working with him and we'll be the Irish and the English Americans in this show. I also look forward to finding some Irish pub near the set. I'm sure we'll find one.”

One final question. Does she get back to Ireland much?

“Oh, yeah, yeah, yeah. There are great Ryanair flights. I mean you can turn up half an hour before the plane leaves and be in Kerry in an hour. I take them all the time!”

"Judy" opens nationwide on Friday, September 27.