And you also probably know his dad, Stellan Skarsgård.
Who, by the way, used to look like this:
You also might know two of Alexander's brothers, Gustaf and Bill.
But there is a chance you don't know the fourth Skarsgård, Valter (here on the right).
Valter is an actor, too, just like the rest of the guys in his family. Recently he was in the show Katlaon Netflix. I watched it, and it was weird but very good.
And now he is also maybe my favorite Skarsgård because his recent tweets got me good.
It started when he responded to this tweet about his family, and roasted himself in the process.
Then the replies started coming in, which made me realize, wow, I LOVE THIS GUY.
Some people started to take it upon themselves to choose a brother, to which Valter responded from the heart:
And then he clarified that the brothers aren't in competition with each other, even if everyone wants them to be:
Basically, he wanted everyone to STOP.
But my absolute favorite is when Valter straight-up denied people asking him to pass things along to his family members.