Rob Kardashian Hits the Town Showing Off Major Weight Loss

Rob Kardashian looks great ... and this picture proves he's turned things around.

Kylie posted this pic of her, Rob and Kendall, with the caption, "5am birthday adventures with my two fav people." Kendall's 24th birthday is Sunday.

As we reported, Rob's emerged from what seemed like self-imposed captivity for a long time. Check out the pic below, where Rob is posing with Kris Jenner. He's Papa Troll Doll, and she's in Dia de los Muertos gear ... in case you can't translate, it means Day of the Dead.

He showed up at Delilah nightclub in WeHo earlier this week celebrating Halloween with other members of fam along with friends. Before hitting up Delilah he was a karaoke bar -- Blind Dragon -- so he's hitting the town again.

There was a lot of buzz when Rob put his arm around Kylie's BFF, Stassi, but we're told they're just friends.

We're guessing we may see Rob again tonight for Kendall's official 24th.