Twitter went into a frenzy on Friday morning after Made In Chelsea's Louise Thompson announced she was engaged.
The star, who is dating personal trainer Ryan Libbey, tweeted she was the "luckiest girl in the world".
The tweet said: "I can't believe it, what a way to propose! I am the luckiest, happiest girl in the world. My love @rwlibbey #mexico wedding!"
The 27-year-old is currently on holiday in Mexico with Ryan, and has been keeping her Twitter and Instagram followers updated with loved-up shots of the couple and bikini photos.
However, dozens of fans were left disappointed after the shock announcement turned out to be a cruel prank by her younger brother, Sam.
Just 40 minutes after the post, Louise tweeted: "Sam you are NOT funny, it's 4.30am in Mexico and I don't wanna have to deal with these embarrassing calls from friends."
It is not the first time Sam has pulled a prank on Louise on social media.
The 24-year-old has been known to steal his sister's outfits and mock her photos by posing as her on Instagram.
Fans were quick to tell Sam off telling him he was "naughty" and "a joker" while others said Ryan was a "nice guy" but they preferred Louise's previous boyfriend, Alik Alfus.
Louise famously turned down Alik's proposal in Made In Chelsea: South of France in August last year, as she had begun dating Ryan.
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