The action star, reprising his role as tough detective John McClane, sobs over Stewart's break-up from Twilight co-star Robert Pattinson in the clip, which aired during Willis' appearance on the Late Show with David Letterman on Thursday (30Aug12).
The hardman breaks down in tears as he tries to deliver his catchphrase, "Yippee-ki-yay, motherf**ker!" in the mock trailer for fake sequel Twi-Hard: With A Vengeance.
He wails, "I'm a little distracted lately, I lost some friends... Kristen and Rob, Bella and Edward - they broke up! They were supposed to be together forever, goddamnit!"
Introducing the sketch, Willis joked to host Letterman, "It's a pretty emotional scene, but very tough. There's a lot of action going on."
Stewart shocked fans in July (12) when she confessed to an "indiscretion" with filmmaker Rupert Sanders and publicly apologised to Pattinson.
