The Return of Zack Morris!

Posted Jun 9th 2009 9:20AM by TMZ Staff

Seriously the best thing ever: Zack Morris was on "Late Night with Jimmy Fallon" last night -- yes, THE Zack Morris, not Mark-Paul Gosselaar.

Good news: He can still do "Time outs" and sings a mean cover of Zack Attack's #1 hit "Friends Forever."

The bad news: He and Kelly Kapowski got divorced.