Kumail was hangin' with a friend Friday at a restaurant in the Los Feliz area of L.A., and it's pretty clear from the pose -- he hasn't lost an inch of mass or muscle.

The 41-year-old stunned everyone with his chiseled pic ... displaying his washboard abs and super vascular arms. He got ripped for his new flick, "Eternals" ... which is set for release in November.

As you know ... Kumail is best known as a nerdy computer geek on "Silicon Valley," which ended last year. During the last season, the nerd's arms were bulging out of his shirt. His career hit a new level in 2017 with his movie, "The Big Sick" -- a true story about his wife.