Branson's Caribbean home was destroyed by fire, as then-Tropical Storm Irene swept through the British Virgin Islands Monday.
Some 20 guests were at the home on Branson's private isle, including Winslet and her children.
All escaped unharmed.
Branson said he was staying in another property around 100 yards away with his wife, Joan and son Sam, 25.
Branson said the fire was likely caused by lightning from the storm.
Tropical Storm Irene walloped the Virgin islands and headed toward Puerto Rico late Sunday and early Monday, strengthening into a hurricane Monday with winds of about 80mph, according to the U.S. National Hurricane Center.
Branson said the house was "completely destroyed" and the fire was not entirely out Monday. He said he plans to rebuild the house as soon as possible.
Branson, 60, bought the island Necker in the early 1980s and began building his mansion in 1982. He also has developed an exclusive eco-resort on the island showcasing renewable energy technology.