Tommy Lee and Son Brandon Reconcile with Heartfelt Hug After Bitter Yearlong Beef

Tommy and Brandon Lee seem to have made up ... after an ugly 2018 between the father and son that began with Brandon knocking him out during an argument.

The Motley Crue drummer shared a photo around midnight of the 2 embracing, captioned simply ... "I love you son." Brandon also posted a video of his dad with him in the studio late Wednesday night ... it looked like they were having a good time.

It's unclear what led to the reconciliation, but it's quite a surprise considering the physical attack that went down in March followed by a criminal investigation ... and a nasty war of words.

As we reported ... the father-son beef culminated when Brandon coldcocked Tommy in the middle of the night, claiming it was self-defense because his dad was drunk. The knockout came on the heels of Tommy taking a shot at Brandon's mom, Pam Anderson, on social media.

Tommy shared a photo of his injuries after the knockout punch, saying he gave his kid everything and he still turned on him.

Cops launched a battery investigation after the incident, but the case was ultimately rejected by the D.A. because Tommy chose not to cooperate.

Still, the 2 continued to go at each other on social media -- especially on Father's Day -- suggesting they were far away from having a loving relationship again.

But, as they say ... time heals all wounds. Or, maybe Brandon just doesn't want to miss Tommy's upcoming wedding.