Here's what's being talked about in pop culture:
• Justin Bieber gave a gift to the musical world just before Christmas: He announced on Twitter, "I'm officially retiring." [Billboard]
• Matt Smith said goodbye to "Doctor Who" in rousing fashion on the BBC show's Christmas episode, which also saw the debut of the new Doctor, Peter Capaldi. [Entertainment Weekly, Vulture]
• "The Wolf of Wall Street" led the Christmas Day releases at the box office. [The Hollywood Reporter] [Billboard](http://www.billboard.com/articles/columns/pop-shop/5847901/justin-bieber-tells-twitter-im-officially-retiring)|
[Entertainment Weekly](http://insidetv.ew.com/2013/12/25/doctor-who-matt-smith-christmas-special/)|
[Vulture](http://www.vulture.com/2013/12/see-matt-smiths-final-moments-on-doctor-who.html)|
[The Hollywood Reporter](http://www.hollywoodreporter.com/news/box-office-wolf-wall-street-667620)|