Despite mutual friend Nick Grimshaw also being in the same car, Pixie has been targeted by 1D fans on Twitter, after they assumed she may be Styles' new love interest.
Grimshaw - who takes over from Chris Moyles on the Radio One Breakfast Show next week - tweeted: "Just reading through some of Pixie Geldof's death threats. Lol."
According to The Mirror, Geldof then retweeted his message - despite Directioners aiming a torrid of abuse at her, writing things like: "I hate you b***h, f**k I'll kill you."
Pixie - who is rocker Bob Geldof's daughter - isn't the first girl to be attacked by Harry's army of avid fans, with ex-lover Caroline Flack and radio DJ Lucy Horobin also coming under fire for being romantically linked to the 18-year old.
The Sun has since reported that Harry has been caught flirting with Alexa Chung at Pixie's 22nd birthday party - after he spent the day watching rumoured girlfriend Cara Delevingne on the catwalk at London Fashion Week.
The tabloid claims Chung made a beeline for Hazza as they celebrated Geldof's birthday at Lucky Voice - leaving together in a cab with Pixie and her man at 1am.
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