Author Paulo Coehlo has his usual moment of realisation; Heidi Klum goes all out for her famously elaborate Halloween bash; P Diddy spends some time with Wikipedia; and Usher seems easily pleased. All this and more in this week's round up of the best celebrity tweets. <em>Follow us on Twitter and keep up to date with the latest in arts and lifestyle news at <a href="http://twitter.com/LifeNationalUAE" target="_blank" title="Twitter: Opens in a new window">twitter.com/LifeNationalUAE</a></em>