The sequel streams on Disney+ on Nov. 18.
In the highly anticipated sequel to 2007's Enchanted, Adams reprises her role as Giselle, a fairy-tale princess who comes to the real world and falls in love with a straight-laced, cynical divorce attorney.
In the sequel, Giselle and Robert (Patrick Dempsey) are happily married, however, when the former princess finds herself somewhat jaded by suburban life, she makes a wish to bring some magic into her world. But the spell has some unexpected consequences -- turning her into an evil stepmother!
"It was so much fun," Adams tells ET's Will Marfuggi about her visit to the dark side. "It was really great to revisit Giselle, with all her optimism and joy and excitement and love for everybody, but then to have that sort of twisted by her wish. I mean, it was really fun to examine what Giselle becomes, like, what are the different aspects of her wickedness?"
Rudolph is a new addition to the Disenchanted cast, playing an adversarial character called Malvina Monroe, whom she described as "totally evil."
"I was just going for pure nasty," she admitted. "It's so big and so much fun. It's the furthest you can go, and I like to go very big, it's really fun."
"We were giggling at how awful she was," Rudolph added. "It's like the most delicious form of drag, you know, 'cause it's very arch, it's very high camp. The wigs, the crown, the nails, the costume. We were literally peacocking the whole time."
Adams wasn't yet a mother when she filmed the first Enchanted, but her daughter, Aviana, is now 12, and Rudolph has two teens of her own. Real-life experience, the actresses said, lent more reality to the storyline between Giselle and her stepdaughter, Morgan (Gabriella Baldacchino).
"I think teens have to naturally distance themselves to you," Rudolph noted. "I think we all went through it... I think it's a natural evolution, which is what makes it so relatable. And I think what's nice about it happening in this story is that you also bring the message of the love is still really there, but kids have to distance themselves from their parents. That's what we do naturally."
"I love teenagers," Adams added. "I love that time where their transitioning into adulthood or learning about themselves, finding their voice. It's interesting to see Giselle go through it, 'cause she's certainly not equipped... but the thing I’ve learned from this is that I have to go through an evolution as my daughter goes through an evolution."
Another big change in the upcoming film is musical numbers for Dempsey and Idina Menzel, who plays Robert's ex, Nancy, who married Giselle's ex, King Edward (James Marsden), at the end of the first film and returned to rule the fairy-tale kingdom of Andalasia.
Following plenty of outcry over Menzel, a Tony winner, not getting her own musical moment in the first film, rest assured, she gets her time to shine in Disenchanted. And it sounds like the singing continued on set, even when the cameras weren't rolling!
"They ask me, off-camera, to always duet with them," Menzel told ET of her co-stars. Especially Amy. She's always asking me. [James Marsden] and I do a lot of '80s duets together, like, "Love Lift Us Up Where We Belong," like, really cheesy stuff like that, and Amy's just always asking me to do Wicked songs."
Disenchanted streams Friday, Nov. 18 on Disney+.