Katy Perry just released her brand new music video for "Last Friday Night (T.G.I.F.)" -- and it's a John Hughes inspired, cameo-packed affair.

The video shows Katy in full-on nerd attire and follows her remembering one wild night at a party next door -- hosted by "Friday" singer Rebecca Black.

"Kathy" gets a makeover, makes out with the popular guy and ends up passing out drunk, all while "Glee" star Kevin McHale -- also playing a geek -- pines for her.

McHale isn't the only celeb to pop up in the video though -- look out for Darren Criss, Debbie Gibson, Corey Feldman, Hanson and even Kenny G!

Check it out above!