The actress will appear in the CBS television reboot of the 1984 movie

Credit: Rick Rowell/ABC/Getty

Thirty years after starring as Superman’s cousin Kara Zor-El in the DC Comics film Supergirl, Helen Slater will appear in the CBS reboot of the movie that made her famous.

“I’ve been acting forever so there can be patches where it can be very quiet, even though you are still a working actress,” she tells PEOPLE. “So I’m very happy about this.”

Even though she’s not allowed to reveal much about her character in the upcoming series, which stars Melissa Benoist and is set to premiere in November, Slater couldn’t be more pleased with how the new version has turned out.

“You just never know because I played Supergirl in 1984, and that’s such a long time ago,” says the actress, 51. “You hope that it won’t be cheesy, and it’s not at all. It’s so sincere and lovely, and the writing is so good. I think it’s going to be a big hit!”

Which isn’t the case for remaking all of her former films: “We are in this age of superheroes, but I don’t think any of my other movies would translate,” says Slater.

While there’s plenty of buzz surrounding her next big role, the actress admits she had to keep her last job playing Don Draper’s guru Sheila in the highly anticipated series finale of Mad Men a secret even from her closest family and friends.

“It was crazy!” she says. “All my friends and family and everybody calling and texting and emailing like, ‘Oh my God, you didn’t tell us!’ ”

“It’s such top secrecy all the way through, and you can’t tell anyone you are working on it. But I had been devoted to the series and such a huge fan so just being part of something so big. I’m just beyond delighted.”

One other project she’s particularly excited about?

“I’m just finishing a children’s record that I wrote based on Hans Christian Andersen’s The Ugly Duckling,” she says.

“I’ve made five records, and the last two have been children’s. I feel like it does something good to the world to tell those stories.”