Is David Beckham’s anti-Brexit stance a celebrity endorsement too far?

Just days before the UK/EU referendum, David Beckham "broke the internet" by announcing on Facebook that he will be backing the campaign to stay within the EU. Following the announcement, the news trended on Twitter for most of the day racking up almost 75,000 tweets in the last twenty-four hours.
Independent experts have responded with contradictory reactions to the news, with the managing director of Ipsos Mori claiming that there is "no clear evidence endorsements like these have any impact."