While auditions continue, presenters Olly and Caroline Flack decided to show off their attire for the day.
With black turned up trousers and a black T-shirt, 'Troublemaker' singer Olly sported perfectly coiffed hair to look like the Rydell High School senior.
We must admit, Olly was missing the white cardigan and those all-important white socks, but we can see the look he was trying to create!
Captioning the photo, Caroline, who also coordinated in a striped top and leather panel skirt, said: "Grease is the word today."
Olly and Caroline are the new co-hosts of The X Factor, having taken over from Dermot O'Leary, who presented the main show for eight years.
Olly and Caroline have worked together before, with their natural on-screen chemistry being a hit on The Xtra Factor, which they presented together in 2011 for two series before Olly left to focus on his music career.
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