ISLAMABAD   -  Kristen Stewart’s casting as Princess Diana set social media ablaze when it was announced back in June. And the actress has admitted she’s nervous about taking on the role in new movie Spencer, especially the task of mastering the late princess’ accent. Kristen, 30, will star in Spencer, which will dramatize a ‘critical’ weekend in the early 1990s, when Diana decided that her marriage to Prince Charles wasn’t working. In a new interview, the actress gushed that she hasn’t been ‘this excited about playing a part, by the way, in so long.’ Kristen added though that there is one thing characteristic she’s desperate to master, admitting: ‘The accent is intimidating as all hell because people know that voice, and it’s so, so distinct and particular’. ‘I’m working on it now and already have my dialect coach.’