“Stand Up Guys” AL PACINO and CHRISTOPHER WALKEN were lunching at LA’s Brite Spot eatery when Al visited the men’s room — and moments later Walken heard loud pounding…and his pal screaming profanities!

Rushing in, he found Al furiously stomping his Smartphone – smashing it into pieces!

"Smart phone, my ass,” Pacino was bellowing. 

Said an eyewitness: “Al had been trying to use the so-called ‘Siri’ feature on his iPhone, but the automated voice kept giving him wrong information. Angrily eyeballing his shattered phone, Pacino snarled, ‘That’s the last time that f****** witch speaks to me!’”

Exiting the john, the stars got strange stares as they headed to their table.

Cracked Walken to their waitress: “And people think I’m the crazy one!”