Big Little Lies director teases what to expect from the high-stakes finale 

French-Canadian director Jean-Marc Vallée has a lot to resolve in Sunday’s finale of HBO’s much buzzed-about miniseries, 

. There’s lip-syncing to tackle and Audrey Hepburn garb to display, not to mention a murder victim and a murderer to unveil. Plus, we have some outstanding questions that need to be answered: Will Celeste (Nicole Kidman) finally leave Perry (Alexander Skarsgard)? Will Perry retaliate? Who is hurting little Amabella (Ivy George)? Who is Ziggy’s (Iain Armitage) father? Will Jane (Shailene Woodley) get her revenge? And will Madeline (Reese Witherspoon) reveal her affair to Ed (Adam Scott)? It’s a lot to dissect in only one hour of television, but Vallée assures us that all those big and little lies will be uncovered.

“Everything moves forward to the resolution,” says Vallée, who is already knee-deep in his next HBO project, the adaptation of Gillian Flynn’s

“The fun part was putting in all these tricks. Like when Renata (Laura Dern) says to Gordon (Jeffrey Nordling), ‘I want to kill her.’ Maybe it’s all between Renata and Madeline. Or maybe it will be between Ed and Nathan (James Tupper). Or maybe between Bonnie (Zoë Kravitz) and Madeline. There are a lot of different scenarios and that was the beauty of the writing. I just followed the plan.”

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Of course, the climax to the series will be Otter Bay Elementary’s big Trivia Night, a fancy gala where the ladies are all dressed up as their favorite version of Audrey Hepburn while the men are clad in their best Elvis Presley attire. (Yes, that is Dern in the brown Hepburn wig from the series’ intro.)

Vallée says he let all the actresses work directly with the costume designer to create their Hepburn look, while he directed the men on what to wear. Witherspoon chose Hepburn’s

white bib tuxedo shirt and satin blue sleeping mask while Kidman chose the classic black dress with the pearl necklace and gilded updo from the same film. For the musical performances, Kravitz’s Bonnie does a mean rendition of an Elvis classic while Ed and Nathan do some serious lip-syncing.

Valle admits shooting the final act — a 20-minute drama fest — was the toughest thing he’s ever done. And this is the guy who followed Witherspoon up a mountain as the director of

. “It was two weeks of shooting through the night from 8 p.m. to 6 a.m. to capture all these different perspectives,” he says.

Of course, as you can see from the promo above, the violence between Celeste and Perry also comes to a head, and that’s after a series of domestic beatings that has already taken a toll on both the audience and the performers.

“It’s tough emotionally but Nicole and Alex just did it. They didn’t complain,” says Vallée, who explains that when the action turned really violent, production would shoot the scene first with her stunt double so Nicole could watch the action play out. That didn’t diminish the difficulty of the scenes. “It’s really difficult to see a guy beating the s— out of a woman,” says Vallée.

Still, Vallée is excited for the audience to experience the finale, which we will dissect after you’ve all watched it Sunday evening. Until then, he keeps his analysis succinct: “I think it’s great.”

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