Twitter was ablaze with gossip earlier (August 20) after One Direction star Niall Horan called Demi Lovato "honey".

Lovato is celebrating her 20th birthday today and Horan, who has previously been linked with the singer, took to Twitter to wish her happy birthday.

He raised eyebrows, however, by calling her "honey", tweeting:

"Happy birthday honey! Have a lovely day! See ya soon."

The term 'Nemi' soon started to trend on the social networking website as fans began to speculate over their friendship.

A potential relationship between the pair has been played down in the past, with Lovato previously admitting she'd rather focus on her career than a boyfriend.