The stakes may be high when you play a real-life person who will eventually watch your performance on the big screen.
But English actress Felicity Jones turned the challenge to her advantage by building a relationship early on with Jane Hawking, the first wife of renowned physicist Stephen Hawking, whom she portrays in the new biopic The Theory Of Everything.
At one point, 70-year-old Jane even lent Jones her clothes.
Speaking to journalists recently at the Waldorf Astoria hotel in New York, Jones, 31, recounted how "immediately warm and open" Jane was at their first encounter, with the English academic even showing Jones a private family album of her and Hawking.
"She wanted to give everything she could to help the performance. Actually, we had discussions with Jane and (her current husband) Jonathan (Jones), and when Eddie came, I answered the door in Jane's coat," she said, referring to British co-star Eddie Redmayne, who plays Hawking.
"It was already a collaboration between Jane and me - she had to suss me out and work out, 'Can I trust this woman to take my life form?' Luckily, it worked out."
While much of the awards season buzz is centred on Redmayne's physical transformation as Hawking, who was diagnosed with Lou Gehrig's Disease at the age of 21, Jones' nuanced portrayal of Jane - a role director James Marsh described as requiring the actress to be "emotionally exposed" - has earned her plaudits as well.
This is especially so because the story is told through Jane's perspective, as a woman who fell in love with an able-bodied man and then made the critical decision to stay with him - and have three children with him - as he degenerated physically into a quadriplegic.
Opening here tomorrow, The Theory Of Everything is an adaptation of Jane's 2008 memoir Travelling To Infinity: My Life With Stephen, a process which screenwriter Anthony McCarten said took 10 years to accomplish from book to screen, from his "initial conversation" with Jane.
Both Redmayne and Jones have been nominated at the upcoming Golden Globe Awards, making them likely shoo-ins for Oscar nominations in a leading role as well.
This is Jones' first major Hollywood breakthrough, after getting notices in critically-acclaimed romance indies such as Like Crazy (2011) and Breathe In (2013) as well as period pictures Hysteria (2011) and The Invisible Woman (2013).
She also had a bit part in last year's The Amazing Spider-Man 2, as Harry Osborn's (Dane DeHaan) assistant Felicia Hardy aka comic book anti-heroine The Black Cat.
Noting how meeting Jane early in the filming process made her job "so much easier", Jones described Jane as being a contrast of her "ladylike exterior" - the embodiment of the ideal woman in the 50s - with "formidable strength, determination and toughness".
"I love having the opportunity to play someone who's vulnerable, emotional and loving, but also tough and strong," she said.
"I get a sense in cinema now that there's a lot of emphasis on women being tough. I'm always wanting to say, 'No, it's both. We don't want to just be vulnerable and diminished; it's about having two sides, more than two sides, about multifaceted female characters."
Jones also said she actively gave input in Jane's characterisation - having learnt that Jane liked dancing, she worked with a movement coach to capture Jane's "balletic way of moving", as well as a vocal coach to master her high-pitched voice.
McCarten said their encounters definitely influenced Jones' portrayal, which he described as an "extraordinary kind of work".
"Jane has made some choices that are quite unorthodox in a standard love story, and (Jones) has to be able to carry the audience through all those turns in the role," he said, referring to Jane bringing Jonathan, a widowed choirmaster (Charlie Cox) who would later become her second husband, to help out with the Hawking family life in the later part of the marriage.
For Jones, exploring the dynamics between Jane's relationship with both men was, in fact, the most poignant part of her role.
"She liked them for very different reasons and there was a moment when she had both, and I thought that was revolutionary. It was bohemian and unconventional, and I thought, 'What an extraordinary woman!'"
Soaring starlets of 2015
Felicity Jones leaves anonymity behind, thanks to The Theory Of Everything. Which other young actresses could also see 2015 as their breakout year?
Tomorrowland (opening May 21)
She's only 24 and already has three TV shows to call her own - Life Unexpected, The Secret Circle and Under The Dome.
But the US actress' biggest score has to be nabbing the starring role opposite George Clooney in Tomorrowland. Directed by Brad Bird, the sci-fi adventure revolves around Robertson's Casey who, with Clooney's Frank, embarks on a mysterious mission to unearth the secrets of a place somewhere in time and space.
Meanwhile, she has also nabbed the lead role in the upcoming Nicholas Sparks-adapted romance The Longest Ride, opening on April 9.
The Man From UNC.L.E. (Aug 13)
Already a fixture in her native country for her roles in television and films, you can't miss this Swedish beauty who has at least six Hollywood movies scheduled for release this year.
Vikander, 26, not only headlines the 17th-century drama Tulip Fever alongside Christoph Waltz and Judi Dench, she's the female lead in spy movie The Man From UNC.L.E. opposite Henry Cavill. She also plays the titular protagonist's (Ben Barnes) enchantress love interest in the fantasy flick Seventh Son, which is currently showing here.
And if these projects don't keep her in the news, you can count on her blossoming relationship with Michael Fassbender to make her a permanent tabloid fixture.
Terminator Genisys (June 25)
Already a fan favourite thanks to hit TV series Game Of Thrones where she plays Daenerys Targaryen, the British actress is set to kick more a** along with the original Terminator, Arnold Schwarzenegger, in Terminator Genisys.
Trading in dragons for huge guns as the iconic Sarah Connor will no doubt help Clarke, 28, continue to dominate geek fanboy territory.
Fifty Shades Of Grey (Feb 12)
Whether the erotic film based on E.L. James' novel is going to be a hit or miss, the 25-year-old US ingenue and offspring of Don Johnson and Melanie Griffith has already secured a position as this year's cinematic temptress.
There's much excitement from fans to see Johnson get it on with co-star Jamie Dornan in her role as student-turned-playmate to his billionaire BDSM-loving character Christian Grey.
This article was first published on January 7, 2015.
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