Alice St. Clair (left) and Kate Middleton
Jim Spellman/WireImage; Matt Baron/Pool/Photoshot/AdMedia
For Alice St. Clair, embracing her inner duchess to portray Catherine, Duchess of Cambridge
is all fun and games – literally.
St. Clair, the the latest actress
to fill Middleton's (sensible) shoes
, tells PEOPLE she got to take on the Queen in a Wii tennis match on the Hallmark Channel's William and Catherine: A Royal Romance
– a scene she says is based on real life.
"They really do [play]," she tells PEOPLE. "Everything in the script is fact."
And although Middleton and the Queen's sporty pastime will play out in the film, which debuts Aug. 27, St. Clair says there's one major moment she won't act out: the royal wedding
"We didn't do those scenes, luckily," she says. "I don't think you can repeat her 'performance' at the wedding."
The film, a biopic prequel that follows Lifetime's made-for-TV movie
, opens the moment Kate
meets Prince William
at the University of St. Andrews.
"A lot of it was using my own experiences about being a 20-year-old," the budding actress explains. "I didn't try too hard to mimic her."
With a few pitch adjustments – "My voice is quite husky," she says – and a princess-worthy wardrobe, St. Clair "changed into [Kate] without really even realizing it."
Her prince is played by Dan Amboyer, a fellow Hollywood newcomer, whom she says lives up to William's double-smooching standards
"[He's] a great kisser," she says. "My boyfriend would be jealous."
And although St. Clair hasn't met the Duchess, she does have her own Palace connection. Her father is the head of security for the royal family, she says, which means her family gets a taste of royalty around the holidays.
As she says, "I think they give out a Christmas pudding every year."