The Pink Ladies wowed the crowd at the Flamingo Las Vegas on Saturday night (3 January) with a rendition of Grease smash hit 'Summer Nights'.
Olivia played good girl Sandy in the iconic musical, while Didi was her friend and mentor (and beauty school wannabe) Frenchie.
How fab to see they're still friends!
Like Britney Spears, Olivia is currently completing a residency in Las Vegas, which is where Didi popped up to join her.
Didi wore a Pink Ladies jacket in homage to her famous character, while Olivia was dressed in head-to-toe leather, much like the more rebellious Sandy at the end of the movie when she drives off into the sunset with Danny (John Travolta).
Grease was released back in 1978 and followed innocent Sandy as she transferred from her school in Australia to Rydell High – only to discover her summer fling Danny is also a student there.
It spawned singalong classics like 'Summer Nights', 'Hopelessly Devoted To You', 'Sandy; and 'Look At Me, I'm Sandra Dee'..
Who else wants to stick on the DVD now?!
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