Stephanie Beatriz
as General Mayhem / Sweet Mayhem (voice)
Jadon Sand
as Finn (voice)
Brooklyn Prince
as Bianca (voice)
Richard Ayoade
as Ice Cream Cone (voice)
Noel Fielding
as Balthazar (voice)
Orville Forte
as Abraham Lincoln
Jimmy Yang
as Enthusiastic Zebra
Gary Payton
as Himself
Sheryl Swoopes
as Herself
Liam Knight
as Duplo/Heart/Star/Sewer Babies
Emmett Mitchell
as Duplo/Duplo Foreman/Duplo Wonder Woman
Sawyer Jones
as Duplo/Heart/Star
Graham Miller
as Duplo/Young Finn
Cora Miller
as Duplo/Star