Cheryl Fernandez-Versini escaped a shark attack while snorkelling with her husband Jean-Bernard during a Caribbean holiday earlier this month.
The pair were staying at a luxury resort when they spotted the blacktip reef shark in the sea, the Daily Mirror reports.
A source told the newspaper: "It was a very scary experience for them both.
"There are warnings up about sharks all year round in that part of the world, but nobody expects to actually see one."
The source added that the beach was evacuated and that Cheryl was left "shaken".
Jean-Bernard later posted a photo of the pair snorkelling online and joked: "Ever heard a Geordie scream, 'It's a f****** shark?'"
The blacktip reef shark has a timid character and is normally easily frightened by swimmers, but they have been known to bite the legs or feet of humans, apparently mistaking them for their natural prey.