The actress and pal Jimmy Fallon laughed uncontrollably as they teamed up for a sketch entitled 'Other Voices'.
The skit, which aired on Fallon’s chat show, saw the pair miming to an impromptu voiceover.
While Fallon, 36, was forced to perform the 'running man' dance, 38-year-old Diaz had to mimic breaking wind.
Diaz had previously surprised the chat show host by entering his studio through a window.
Wearing a black top and tight-fitting white trousers, the Bad Teacher star shouted to get Fallon's attention as he looked for her at the regular entrance.
Fallon, who has been friends with Diaz for years, then helped her down off the window sill as she wrapped her legs around his waist.