Friends of the pair have reportedly revealed they are simply enjoying each other's company, having recently danced all night at Public nightclub in Chelsea alongside Harry's friend Guy Pelly.
"They have been to Public nightclub a couple of times and get along well. It's ironic because Mollie fell for David [Gandy] over Prince Harry, but now she seems very taken with Harry," a source told The Mail On Sunday.
"They're having a lovely time together but she won't say anything publicly because she knows that will mean the end of it.
"She loves the publicity so she is happy to drop a few hints and keep people guessing."
King kept tight-lipped over the romance at a recent charity event.
Watch the video for The Saturdays' 'Higher' below: