The cast of "Keeping up with the Kardashians"

The pair - who flew out to Mammoth Lakes, California for a ski trip on New Year's Day - have  become "incredibly close" in recent weeks but fans won't get to glimpse their budding romance as the 'Story Of My Life' singer has refused to to be filmed because he wants their relationship to remain "personal, not professional".

A source told the New York Daily News newspaper's Confidenti@l column: "Harry has told Kendall that he will not appear on 'Keeping Up With the Kardashians' under any circumstances, Harry does not want his love life played out across the world on TV."

Kendall's mother Kris Jenner - who is also executive producer on the show - has given her daughter's new relationship her blessing, particularly because she thinks it will be good for the programme's ratings if the One Direction hunk eventually agrees to appear.

An insider added: "Kris has a double interest. Obviously she wants her daughter to have the best relationship with Harry but as the show's EP knows how much of a draw footage of the pair could be."

Harry and Kendall,18, first sparked dating rumors in November when they were spotted leaving Craig's restaurant in Hollywood and despite a number of rendezvous - including the 19-year-old singer jetting from the South of France to London to see the model last month - the pair have still not confirmed their romance.