AceShowbiz - Pop star Justin Bieber thrilled a young British fan suffering from a rare genetic condition on Sunday, December 5 after surprising her during his stay in London. Hayley Okines, who suffers from the rapid aging condition Progeria, was able to meet her pop idol thanks to the efforts of a group of Bieber fans who launched a campaign on Twitter.com to bring them together.

Bieber signed autographs and posed for photographs with Okines and her family - and topped off the special visit by offering her tickets to see his next concert in the U.K. He also offered free passes to the kind-hearted group responsible for putting him in touch with Okines.

In Twitter.com messages to the fans who organized the visit, Bieber writes, "U did a good thing. And you were right she has a great smile. It was actually kinda funny. She had no clue (about the meeting) and when she saw me she screamed and everyone was like what the?!?!"

"She was real sweet and I offered her tix (tickets) for the show in the UK when I'm back. I think you should go with her then too... The fans did a good thing. Glad I could help. Thanks for introducing us. She is a sweet girl."