The businessman was left devastated after fire ripped through his luxury property on Necker Island in the British Virgin Islands earlier this month (Aug11).
Branson was due to join a team of stars swimming the Irish Sea from Dublin, Ireland to Holyhead in Wales in aid of cancer charities next month (Sep11) - but he's now pulled out to spend time with his family following the disaster.
Boyzone singer Ronan Keating, who is also taking part in the event, told followers on Twitter.com, ""Just found out richardbranson has had to pull out of JoinTheSwim. Devastated but totally understand. Hope you (sic) doing ok mate.""