<p><br /> Robin Williams says he has never been confused for popstar Robbie Williams despite having similar names.<br /> </p><p><br /> The actor was quizzed about the possible case of mistaken identity when promoting his new movie World's Greatest Dad:<br /> </p><p><br /> "Not at all. It takes a lot of medication to confuse us."<br /> </p><p><br /> Robin, 59, also said he has never been confused with tennis star Serena Williams either:<br /> </p><p><br /> "Never. I just love watching... you don't even need to watch, you just put on Wimbledon, turn off the picture and when Serena plays Sharapova it's the closest thing to phone sex!"<br /> </p><p><br /> World's Greatest Dad is released in cinemas across the UK on Friday 24 September.<br /> </p>
