Khloe Kardashian, Lamar Odom Back Together ... For a While

The plot thickens with Lamar Odom and Khloe Kardashian ... they both showed up at Kanye West's concert in Downtown L.A. Monday night ... but just how close they were is up for debate.

We got this pic of Lamar showing up -- ALONE -- at the back of Staples Center. We also got far off shots inside the venue of Kylie waving to someone.

And there's this. Khloe tweeted a pic of the stage and wrote, "Yeezus."

There are multiple people who were tweeting they saw the whole Klan together at the concert -- including Khloe, Lamar and even Bruce.