The Mean Girls actress is nominated for Best Supporting Actress for her performance as Marion Davies in Mank

Amanda Seyfried is sharing her first Oscar nomination with her biggest fan.

The actress, 35, who's nominated for Best Supporting Actress at this Sunday's Academy Awards for her performance as Golden Age film star Marion Davies in Mank, reveals to PEOPLE how much her dad's admiration means to her.

"I get so much from his pride," the star says. "I want to share these wins with him."

One of those wins included the Montecito Award at the 36th annual Santa Barbara International Film Festival (SBIFF) in early April. For 35 years, SBIFF has become one of the leading film festivals in the world and funds raised through the festival directly support SBIFF's yearly free programs that serve over 14,000 people. In addition to Seyfried, additional honorees and panelists at the event included Bill Murray, Sacha Baron Cohen, Riz Ahmed, Maria Bakalova, Kingsley Ben-Adir, Andra Day, Sidney Flanigan, Vanessa Kirby, Tahar Rahim, Zendaya, Carey Mulligan, and Delroy Lindo.

Set in Hollywood during the 1930s, Mank tells the story of screenwriter Herman J. Mankiewicz and his turbulent relationship with director Orson Welles as they co-wrote the script for Citizen Kane. Oldman plays Mankiewicz, known as Mank by those close to him, alongside Tom Burke as Orson Welles, and Seyfriend as Marion Davies, a Broadway actress who was a mistress to the newspaper giant William Randolph Hearst. The film was a passion project for acclaimed director David Fincher (The Social Network) since it's based on a screenplay by his late father Jack Fincher.

MANK (2020)Amanda Seyfried as Marion Davies
Amanda Seyfried in Mank
| Credit: NETFLIX

Seyfried says her own father is "a lover of old movies," and she cherished being able to invite him to the set of Mank while she was shooting. "It was just like a kid in a candy store watching this man who just has such a passion for this era really come alive with questions for the people working there," she marvels.

Despite her dad's love for the period, Seyfried confesses she never pictured herself as Davies.

"My dad would say, 'Oh, it would be amazing if you could play so-and-so or Betty Davis,'" she recalls. "It was never a goal of mine. I guess because I'm pretty realistic, I think, and I don't have many expectations. I do have goals, but that just wasn't one of them. I didn't see myself being able to fit into that era."

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amanda seyfried
Credit: Tristan Fewlings/Getty

Seyfried says being offered the role of Davies "felt like it was way too good to be true." "I was kind of intimidated by her and by the idea of it," the mom of two admits. "But when you're given an opportunity like this, really just on a silver platter — David Fincher being the silver platter — you think, 'Well, life's too short to worry about the things that I can't do. Why not just try to figure it out and do your job.'"

"The whole thing was a surprise," she adds. "The whole David Fincher of my life right now is a surprise, and I'm constantly in awe of the fact that I got to work with him and help him create this world. Sometimes I'm just at a loss for words."

The 93rd Academy Awards will air live on Sunday, April 25 starting at 8 p.m. ET/5 p.m. PT on ABC.

For more on Amanda Seyfried, pick up this week's issue of PEOPLE, on stands now.