Lamar Odom was so excited about his sis-in-law Kim Kardashian's pregnancy announcement ... he hit the club to toast her ... by himself.
Okay ... LO was probably heading out anyway, but we caught up with him outside Greytsone Manor shortly after Kanye West dropped the baby news -- and he summed up his joy in 3 words: "Great. Great! Awesome."
Alright, it was 2 words ... with a repeat.
Lamar tweeted a few more, saying ... "There's nothing like bringing life into this world! Let's keep Gods blessings coming!
If you think it's odd he was solo -- check out the video -- Uncle LO addressed rumors about his missing wedding ring ... and he and Khloe possibly breaking up.