Earlier this month, the HSM star revealed she took her daughter Jupiter, 4, to see her niece, Mikayla, portray Sharpay Evans, the same role she originally played, in a stage production of the 2006 Disney Channel Original Movie.

Now, Tisdale is opening up about how she was -- and wasn't -- willing to help Mikayla prepare ahead of the show.

Mikayla's costume looked eerily similar to the original outfit Tisdale wore during the film's "What I've Been Looking For" scene, according to her Instagram Stories.

But during an interview at the Bush's Bluey Baked Beans launch event at CAMP in New York City on May 14, she tells PEOPLE the look was a spot-on recreation.

Before the actual production, Ashley says, her sister Jennifer "tried" to borrow some of the original Sharpay costumes for Mikayla: "My sister's like, 'Can we borrow the Bop to the Top dress?' And I'm like, 'No, you cannot do that.' It's, like, an iconic dress."

"It's all in my storage unit. I actually have all of her clothes from the first movie, of course," explains the Being Frenshe founder. "But my sister was so genius and literally did all of that for my niece."

After learning Mikayla was set to play Sharpay, Ashley recalls, "I thought my niece would ask me for like, you know, any type of advice. Nope. She did it on her own. She was like, 'I'm gonna do this my own way,' and I was surprised by all of it, the outfits, everything."

"She really wanted Gabriella, let's be honest," continues the "He Said She Said" singer, referencing Vanessa Hudgens' character from the HSM franchise. "She was kind of bummed that she got Sharpay. I'm just kidding. I think it's just because it's like, I'm her aunt. She's like, 'Oh God,' you know? But she did such a great job."

Following the performance, Ashley has been open on social media about Jupiter's newfound HSM obsession. "When she's seen the movie in the past, like, she never really cared about it, but I think seeing my niece in the play, play me, has just changed her, so she had to watch all three movies," she said on TikTok. "She will not stop listening to the music."