It was just a day ago that the loved-up couple made their red carpet debut at the TV BAFTAs in London, and made every inch the picture perfect pair.
However, a new Instagram snap posted to Louis' Instagram account gave us an insight into their bathroom antics on a Monday evening.
Similar to Kim Kardashian and Jennifer Lopez's 'battle of the bums' at the Met Gala, Lucy and Louis decided to go one step further - by almost baring all!
Olympic gymnast Louis and former TOWIE star-turned-fitness-expert Lucy proudly flaunted their derrières with their bum cheeks on full display.
While Lucy showed off her bottom in pink leopard print pants, former Strictly Come Dancing winner Louis was giving her a run for her money with a bright blue pair.
Captioning the photo, Louis said: "Who has the better derrière? Me or @lucymeck1 haha #battleofthebutts."
We'll leave that for you to decide...
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Lucy Mecklenburgh - life after TOWIE: