It was Christmas 2012 when Millie and Rosie Fortescue were told by Francis Boulle on "good authority" that lothario Spenny had been unfaithful.
It didn't take long for Millie and Rosie to march over to Spencer and Louise at a party, and all hell broke loose.
"I think you owe Louise the truth." Millie interrupted. "Don't act like you don't know what we're talking about. The fact that you have been unfaithful to your girlfriend... Spencer just be honest."
Denying the claims, Spencer blasted Millie for coming over with "s**t like that from an unreliable source like Francis".
Going back and forth with the exchange of words, Millie shouted, "This is what you've done, this is what you've f**king done to her," followed by the now-epic slap...
Relive it all below:
The slap was so effective that Spenny's gelled hair came out of place, and, quite understandably, he was left rather shellshocked by it all.
In denial after receiving that almighty slap, Spencer responded: "Are you taking the p**s? You must be taking the absolute p**s?"
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