Harry Styles is a master of vague tweets, and the One Direction singer's latest message has left fans totally confused. He wished someone happy birthday on Twitter, and everyone has been wondering if he's tweeting about a friend, a family member, or a love interest. (It's also both Britney Spears and Charlie Puth's birthdays.) However, Directioners have pointed out that he's referring to a fan named Kelcey Hallinan, who passed away two years ago.

He liked the photo her older sister posted in honor of her birthday along with the caption, "Happy 21st birthday to heaven's most beautiful angel. Miss you more than words can ever say, little sissy. Celebrations will still occur in your honor of course."

When she passed away in November 2013, he tweeted a touching tribute in her honor.

It's sweet that he's remembering her like this, even if it kept everyone guessing because he didn't identify her by name.

Did you know who Harry was wishing happy birthday on Twitter? Tell us in the comments!

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