Oprah Winfrey, Reese Witherspoon and Mindy Kaling are opening up about their time together starring in Disney's upcoming adaptation of Madeleine L'Engle's beloved children's fantasy, A Wrinkle in Time.

ET's Cameron Mathison caught up with the stars on the red carpet at Disney's D23 Expo at the Anaheim Convention Center on Saturday, where they dished on the fun, meaningful conversations they shared while spending hours together getting ready for their roles.

WATCH: Ava DuVernay Shares Stunning First Look at 'Wrinkle in Time' Cast!

"We had a lot of major conversations in the hair and makeup room every morning. It was great camaraderie from the very first day," Winfrey shared. "Reese was head DJ, down at the end chair, playing music that I hadn't heard since 1945. Who knew that she had all this soul sister in her? Al Green [was] rocking us out and so were a whole lot of people."

"It was an incredible experience, just to be with each other and to share in this sort of newfound adventure," she added.

For Kaling, the thing that blew her away the most about her A-list co-stars was their generous spirit.

"The two of them are known for their generosity, but it's not just generosity of things -- they want to share physically with you. Their favorite English muffins, their favorite music, their favorite makeup brands, but also with advice and life experience," Kaling recalled. "You just come in every day and learn something incredible."

WATCH: Chris Pine on Working With Oprah Winfrey on 'A Wrinkle in Time': 'She's a Force of Nature!'

In A Wrinkle in Time, Winfrey, Kaling and Witherspoon star as a trio of eccentric celestial beings who accompany a young girl named Meg (Storm Reid) on a magical, fantastical journey to locate her missing scientist father (Chris Pine).

For some of the film, production took place in New Zealand and Witherspoon said the group made the most of their time -- thanks to her meticulously-planned schedules.

"[I said], 'You guys, we're gonna wake up at 5, and then at 7 we're gonna hike, and at 9 o'clock we are going to a vineyard," the Big Little Lies star recounted.

WATCH: Oprah Winfrey, Reese Witherspoon and Mindy Kaling Are Basically on Vacation While Shooting 'A Wrinkle in Time'

"'Then we'll go to a yoga place and then we're gonna take a helicopter,'" Winfrey added, laughing. The media mogul said their goal was to "squeeze the juice out of this orange every minute."

A Wrinkle in Time -- penned by Wreck-It Ralph screenwriter Jennifer Lee and helmed by Selma director Ava DuVernay -- flies into theaters March 9, 2018. Check out the epic first trailer below.