"I didn't want [them] to fall into the wrong hands, because it's actually a cast of my actual breasts inside," the actress tells PEOPLE
Lea Thompson Back to the Future II Michael J. Fox
Credit: Mary Evans/UNIVERSAL PICTURES/AMBLIN ENTERTAINMENT/Ronald Grant/Everett Collection

Lea Thompson made sure to leave the set of Back to the Future Part II with one very special souvenir!

Speaking to PEOPLE in celebration of Back to the Future's 35th anniversary and the release of Back to the Future: The Ultimate Trilogy, the 59-year-old actress says she took her prosthetic breasts home after filming on the project was completed.

"From Back to the Future Part II, I took my prosthetic breasts," Thompson tells PEOPLE. "I didn't want [them] to fall into the wrong hands, because it's actually a cast of my actual breasts inside."

"So I was like, 'I'll take those, thank you very much,'" she adds. "But they got really smelly because they were latex and I threw them away."

Thompson wore the artificial piece in the time-traveling film after her character Lorraine was forced to get implants when she married Biff Tannen within the 1985 alternative timeline in the sequel.

Lea Thompson
Lea Thompson
| Credit: Rob Latour/Shutterstock

The Back to the Future film trilogy follows Marty McFly (Michael J. Fox) and his eccentric scientist friend, Doctor Emmett Brown (Christopher Lloyd), as they use a DeLorean time machine to time travel through different periods throughout the history of their fictional Californian town.

Remembering her time throughout the film saga since the original Back to the Future hit theaters in 1985, Thompson says she looks back fondly at her time starring in all three films within the series.

"I feel like I've had such a great life and a great career," she says. "And I'm so happy that the thing that I'm most known for is such a great movie that's had such an effect on people's lives."

"Lorraine McFly was such an interesting part, and as an actor, was such an opportunity to show my range," she adds. "So I feel incredibly blessed."

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

Thompson credits the different levels of the film with why audiences, old and new, still have love for the treasured film trilogy to this day.

"I think that there are so many levels to the movies that depending upon how old you are or what place you are in your life, you can get something different," she says.

"It could be as simple as like, 'Woah that car's cool,'" she continues. "Or it can be, 'What a great message to tell my children' that if you're like George McFly, and you have the courage to stand up for yourself and the people you love at the right moment, you can change your life and your family's life."

"It's just like the perfect storm because it was nostalgic about the 50s and it's nostalgic about the 80s," she adds.

RELATED VIDEO: Lea Thompson Opens Up About a Possible 'Back to the Future' Remake!

And now, to commemorate the film's longevity and celebrate its anniversary, Universal has released Back to the Future: The Ultimate Trilogy on 4K Ultra HD.

Released on Tuesday, the collection boasts over an hour of brand new content, including a sneak peek at the new Back to the Future musical show and test footage from young stars who auditioned for roles in the hit franchise — like Ben Stiller, Billy Zane and Kyra Sedgwick.

Lea Thompson Back to the Future
Lea Thompson in Back to the Future
| Credit: Moviestore/Shutterstock

And while Thompson says that she still cannot believe the impact that Back to the Future has had on movie fans and entertainment culture as a whole, she is honored to be a part of its everlasting influence.

"An artist wants to make an impression and a mark on the world and so what could be better?" she says. "I can't tell you, it means so much."