We're hot for teacher!

Everyone's favorite substitute teacher, Gwyneth Paltrow, is back on the set of Glee for the hit show's 100th episode. The Oscar winner will be reprising her role as sassy sub Holly Holliday. Clearly Gwynnie is just as excited about as we are about her guest starring role -- posting pics from Paramount's backlot on her Instagram.

The mom of two shared a photo in her sexy teacher's costume as well as a selfie of herself and Glee co-creator Ryan Murphy giving fish faces with the caption "me x ryan murphy (lips) #glee."

The Ironman star first rocked out on Glee in November, 2010, marking her first appearance on a scripted series. The guest appearance was a hit with fans and yet again Ryan reached out to the actress in December and invited her to Chace Crawford's love interest in the 100th episode.

The 100th episode will be shown in two parts on March 18th and March 25th and centers around glee club-hating principal Sue Sylvester (Jane Lynch) as she finally succeeds in ending New Directions after years of trying to squash the plucky singing group.

Other original cast members including Heather Morris (Brittany), Harry Shum Jr. (Mike), Mark Salling (Puck), Amber Riley (Mercedes), Kristin Chenoweth (April), Blaine (Darren Criss), Kurt (Chris Colfer) and Sam (Chord Overstreet) are set to reprise their roles for the 100th episode.