Snoop Dogg -- REUNITES with Suge Knight!! [Update]

1:39 PM PT -- The picture was taken Monday night at AV Club in Los Angeles.

Sources tell TMZ ... Snoop had performed at the club that night ... and Suge showed up to see the performance.

After the show, we're told Suge walked over to Snoop's VIP table and the two hit it off like old times ... hugging, laughing and taking pictures.

It's the reunion that NOBODY saw coming ... Snoop Dogg hanging out in a nightclub with former Death Row Records honcho Suge Knight ... smiling and partying together during a recent night out.

Snoop just posted the photo to his Instagram page ... with the caption, "N d club wit Suge miss those death row days!"

It's unclear when and where the photo was taken.

Snoop -- a former Death Row rapper -- hasn't been friendly with Suge since the '90s.

Snoop has previously explained that Suge and Tupac got pissed at him because they felt he didn't have their back when Death Row was beefin' with Bad Boy Records.