She may have been tucked deep in the shadows of Pride and Prejudice, but Mary Bennet — the unassuming, oft-forgotten sister of the beautiful Jane and whip-smart Elizabeth — is ready for the spotlight.

On Wednesday, May 6, The Other Bennet Sister (which saw record-breaking numbers upon its release in the U.K. earlier this year) finally makes its U.S. debut on BritBox.

Last July PEOPLE visited the set of the highly anticipated drama, an adaptation of Janice Hadlow’s 2020 novel of the same name, where the cast — stacked with TV veterans like Indira Varma (Mrs. Gardiner) and Ruth Jones (Mrs. Bennet), along with young talent like Poppy Gilbert (Elizabeth Bennet) and Maddie Close (Jane Bingley) — were buzzing with palpable energy and excitement surrounding the project.

And of course, the cast threw their support behind Ella Bruccoleri, 29, who tackles the role of Mary, a bookish young woman eager to defy her family’s expectations and ultimately finds herself torn between two suitors, Mr. Hayward and Mr. Ryder, in her first major starring role.

“I think she’s an astonishing actress,” an emotional Varma, 52 — who had her last day shooting during PEOPLE’s visit — said of Bruccoleri after wrapping her final scene. “She takes the work really seriously. If you’re No. 1 and you’re in every single scene, you’ve got to conserve your energy and be so prepared. She’s beyond prepared, but at the same time she is open to play and she’s responsive.”

In the show Mrs. Gardiner becomes a mentor and guide for the willful Mary, and Indira says life imitated art. “Mrs. Gardiner has a moment where Mary says, ‘Oh, I think I might be a governess, if that’s all that’s left for me.’ And Mrs. Gardiner says, ‘You’d make a brilliant governess because you have so much to pass on. And not only would you be a brilliant governess, but you’d make a great guide to a young woman trying to find her place in the world.’ And I think that’s what Mrs. Gardiner has done for Mary.

“I think it’s much-needed for this time. Women need to lift each other up, empower each other, see each other and be given space not to conform,” continues Varma. “[Ella and I] just had a really good repartee.”

As with many young women, much of the cast grew up idolizing the witty and independent Elizabeth Bennet, who found love with the proud but kindhearted Mr. Darcy in Pride and Prejudice. In this spinoff, Jane Austen’s beloved protagonist becomes a supporting character — making way for her sister to take center stage.

The chemistry is effortless during a scene featuring all the Bennets shot at Darcy’s Pemberley estate (filmed at Badminton House, the family home of the 12th Duke of Beaufort in Gloucestershire), and the stars say the rapport was easy from the start.

“We had a rehearsal for the ball, but they’d only cast us and Ella by then,” says Gilbert, 27, tucked in her trailer with Close during a break on set. Adds Close: “It was amazing. We got along instantly, to be fair.”

During their first read-through with the rest of their onscreen siblings, “we just fell into the roles,” adds Close, 27. “It all just kind of came together.”

Being able to dig into “quite an unflattering side of Lizzie” was also a treat. “The pretty privilege that the four sisters have that Mary doesn’t feel she has, and the witty privilege that Lizzie wears like a sort of badge that means she’s really ignorant to what Mary’s gone through… we delved into in a big way,” says Close. “I don’t think it takes away from the love of the character that people have. The more real somebody feels, I think the closer you feel to them.”

Kitty (Molly Wright) and Lydia (Grace Hogg-Robinson) also get deeper character development through Mary’s eyes. “There’s quite a lot in the script that deviates a bit from the sort of bubbly, silly Lydia that we’re all used to,” Hogg-Robinson, 30, says of the more “mature” Lydia viewers get to see. Teases Wright, 30, of Kitty: “She’s absolutely joined at the hip with Lydia and is kind of very easily influenced, and then she gets a bit of a backbone, strays from her a little bit and gets a bit of independence. You see her older and happy.”

For matriarch Mrs. Bennet, Jones said she listened to The Other Bennet Sister audio book purposefully after reading the script. “Because then you’re looking at the script in their own context and for their own merits without being influenced by the book,” Jones explains. “The book helped then, once I knew what Mrs. Bennet’s journey was going to be, to color things a bit.”

Bringing more depth to an iconic character was “a really joyous experience,” adds Jones, 59. “In Pride and Prejudice it’s about her relationship with Lizzie and her need to get her daughters married off. Mary is the bane of her life because she will not conform to what Mrs. Bennett’s expectations are, how she thinks life should be lived — and it absolutely drives her insane.”

Jones calls Bruccoleri’s performance in the series “nuanced, incredible and real,” adding that she “absolutely captured this believability in the role.”

The Other Bennet Sister is set for release on May 6 on BritBox.