Michael B. Jordan Celebrates Oscar Win At In-N-Out, Fans Go Wild

Michael B. Jordan turned an In-N-Out into a full-blown pep rally after nabbing his Oscar ... with fans erupting as he rolled in, trophy in hand.

The "Sinners" star beelined it to the popular fast-food joint after Sunday night's ceremony -- with his shiny Best Actor statue -- still dressed to the nines.

Check out the video ... patrons lose it as Michael waits at the counter for his food -- swarming around him, hooting and hollering while shouting "congratulations!"

Everyone wants a glimpse of MBJ ... with fans even standing on chairs and booths to film the actor as he soaks in the moment.

Even the In-N-Out workers look stunned ... handing Michael a paper and pen so he could sign a few autographs. MBJ happily poses for pics in front of the counter ... clutching his Oscar and flashing a huge grin.

No takeout order here ... Michael slips his way through the massive crowd to sit down at his booth to dig into an ELITE order. Based on the eye test ... looks like two Double-Doubles and plenty of fries, pro move.

Michael can hardly take a bite without fans asking him questions and cheering him on.

Either the crowd became a bit too much -- or the whole thing was a photo opp ... because after taking a few bites, Michael and his team headed for the exit.