Wow, Katy Perry sure went all-in for the new retro-tastic music video for “Last Friday Night (T.G.I.F.),” the fifth single from Teenage Dream.

Adopting the guise of 8th-grade goober Kathy Beth Terry several days ago, Perry posted on Facebook and tweeted as her retainer-wearing alter ego, following the timeline of events chronicled in “Last Friday Night.” That real-time approach built up to the premiere of the music video today on Funny Or Die. It’s actually more like a mini-movie, and I’m beyond relieved it’s not a literal retelling of the song, because I had my reservations about a 13-year-old singing of ménage a trois, taking too many shots, getting kicked out of bars, maxing credit cards, et al.

Rebecca “Gotta get down on Friday” Black plays Kathy Beth Terry’s neighbor/rival who throws a righteous party and gives KBT a head-to-toe, glammed-up makeover (as seen on the single’s cover art). I don’t wish to ruin the surprise of the other cameos, but some of your favorite stars from the ’80s, ’90s and today pop up in “Last Friday Night.”

Perry’s music video for “Last Friday Night (T.G.I.F.)” is a fluorescent-hued hoot and couldn’t be more perfect for this bouncy summer single, which will likely become her fifth straight #1 hit (and sixth overall).

I must also offer an on-the-record apology to Katy Perry, as it had slipped my mind that it was she, not Lady Gaga, that brought the sax back to pop music first. Kudos (plus, cheesewise, Kenny G > Clarence Clemons).

Purchase Katy Perry – “Last Friday Night” (T.G.I.F.) via iTunes, Amazon MP3.