ET has the scoop.

Newlyweds MARIAH CAREY and NICK CANNON enjoyed a magical night at Six Flags Magic Mountain in L.A. on Tuesday evening -- and the star couple invited only ET's KEVIN FRAZIER and our cameras inside the theme park with them! Tune in to Entertainment Tonight on Wednesday to see all the romantic fun.

Mariah couldn't believe her eyes when she and Nick arrived in a Rolls-Royce at Six Flags, only to find it transformed into a private party palace just for them -- a special surprise arranged for her by Nick!

The normally packed theme park played host to the newlyweds and an exclusive guest list of 100 invitees, and the entire premises was decorated in purple and pink balloons, not to mention signs reading "Nick and Mariah: A Love Story."

Our own Kevin Frazier got in on the fun, too, taking a roller coaster ride with the couple and offering them a unique wedding gift -- a blender! Mariah assured Kevin the present would be perfect for making protein shakes with, so she can keep her new sexy figure. There's even more on their action-packed evening from Kevin right here!