Medium Haisrtyle Celebrity

  Selena Gomez launches Disney Channel HD with a special showcase at the Hospital Club in London.   Jennifer Aniston at the Los Angeles premiere of "Horrible Bosses" held at the Grauman's Chinese Theater, Los Angeles.  Actress Cameron Diaz is seen arriving for the Moscow premiere of Bad Teacher.   Model Irina Shayk attends the 9th annual Russian Heritage Festival at The Metropolitan