LOS ANGELES, June 29 — Kristen Wiig stopped by the sets of The Tonight Show and Jimmy Fallon got her to join him in a "Mad Lib Theatre” sketch.

As part of the sketch, the stars have to read from a script that included some silly words and phrases that were randomly chosen by Wiig before they started.

The words are then used for a comical sketch where Wiig plays a doctor and has to break some pretty bad news to patient Fallon.

Need we tell you the hilarity that ensued once the sketch started? Check out the clip for yourself.

Watch Kristen Wiig play a doctor to Jimmy Fallon in this hilarious ‘Mad Lib Theatre’ sketch.