Poor, poor Kourt.
The source says of Disick:
Tricking Oz and defeating the good witch is SERIOUS business, but apparently Mila Kunis thinks it's HIGHlarious!
The stunning starlet clearly could NOT hold back the giggles while she filmed Oz The Great and Powerful and the results are almost as entertaining as the movie itself.
Can we be her BFF already??!
Ch-ch-check out the blooper reel (above)!!!