Justin Bieber is set to meet a 9/11 victim's daughter after a request from US President Barack Obama.

The 'Baby' hitmaker has implied he will keep a promise made by the American leader that he would arrange a meeting between the 17-year-old pop superstar and 14-year-old Payton Wall.

The 17-year-old singer wrote on twitter yesterday (12.05.11): "I think you're wrong. Pretty sure President @BarackObama will keep this promise."

Payton - whose father died when he was trapped in the World Trade Centre during the 9/11 terrorist attacks in New York - first tweeted the 'One Less Lonely Girl' singer in February.

She wrote: "hey! I have an awful life story and without your music idk if i could have survived. do you think i could send you a letter? (sic)"

But when the New Jersey Girl did not receive any response, she wrote a letter to President Obama and the White House promptly invited her to meet him at Ground Zero in New York City, where he told her he "knows Justin" and made the vow to arrange a meeting with her idol.