Those wild star cameos in 'Lego Movie 2' explained, from Bruce Willis to Velma (spoilers!)

Warning, some spoilers ahead! Read this after you've seen "The Lego Movie 2."

The jokes and minifigure celebrity cameos come fast and furious in "The Lego Movie 2: The Second Part."

Hero pair Emmet (voiced by Chris Pratt) and Wyldstyle (Elizabeth Banks), along with Batman (Will Arnett), front a brick army of A-list appearances that even include Ruth Bader Ginsburg.

Director Mike Mitchell still finds himself surprised by small details the film's head of story, Trisha Gum, worked into the animated movie (in theaters now).

"This is the 'Where’s Waldo?' of filmmaking. There is so much going on here," says Mitchell. "Even now, I'll be watching and go, 'Oh, wow, look at that guy! I didn't see that before.' "

We asked Gum and Miller to explain some of the more surprising appearances.

Supreme movie justice: Ruth Bader Ginsburg in 'Lego Movie 2'

'The Catchy Song': 'Lego Movie 2' director apologizes for that earworm

Question: Why does Velma from "Scooby-Doo" make a solo appearance?

Trisha Gum: It’s just so obscure and out of nowhere. You’re used to seeing Shaggy or Scooby-Doo. But not Velma on her own.

Mike Mitchell: Every time we’ve screened it, with just Velma appearing with glasses and the brown sweater, the whole crowd knows who she is and people go crazy. Besides, in a post-apocalyptic world, Velma would have been the only one to have survived. The other kids wouldn’t have made it. 

Q: Lego Bruce Willis makes a "Die Hard" cameo. Did the real Bruce Willis voice that appearance?  

Gum: Thank goodness he agreed. We already were animating him.

Mitchell: He recorded in the studio. He took his minifig crawling through air ducts very, very seriously, which made it even funnier to us.  

Q: Wonder Woman appears, but it's not Gal Gadot voicing her, as some have speculated.

Mitchell: It’s voiced by Wonder Woman from the first "Lego Movie," Cobie Smulders. Gal Gadot didn’t have time; she was off shooting. We would have loved to have her. 

Gum: There are three Wonder Women, all different toy versions. There’s a minifigure, a Lego Friends doll and a Lego Duplo, different toy versions for different age groups. We figured there are no rules since this story features a (younger) sister's Lego world. She doesn’t care if there are three Wonder Women. 

Q: Lego Abraham Lincoln screams, "I had theater tickets tonight" before being sucked into storage. Too soon?

Mitchell: Too soon for that joke? The question was, is it too late? We decided, no, it’s not. It’s just the right time.

Gum: I wonder if the kids are going to get it.

Mitchell: For anyone disturbed by it, we made sure that a cat flew into his lap.

Q: Out of all the world's basketball players, why are Gary Payton and Sheryl Swoopes appearing together?

Mitchell: Why wouldn’t they be in this world? (Producer) Chris Miller is a huge fan of Gary Payton. And we’re big fans of Sheryl and thought it would be cool to give a shout-out to one of the greatest WNBA players.

Q: Maya Rudolph plays the mother of the children playing with Legos. But Will Ferrell, who made a surprise appearance as the human father in the first "Lego Movie," is only heard, not seen. Why? 

Mitchell: Will was available. But you can hear he’s not helping his wife at all with the parenting. We thought it was more of a mom's story. And the joke where Maya steps on a Lego brick and compares it to childbirth, that was all her.

Gum: We didn’t want to make this story without Will, though. We’re glad he came back to play in this world.