Joely Richardson helped save a man's life when he jumped into the River Thames.

The 54-year-old actress was filming her new series 'The Rook' when she heard a ''huge splash'' caused when the unnamed male leapt ''off the bridge'' into the water, so she alerted security, who managed to fish him out of the river, even though he'd drifted a ''terrifying'' distance away from the shore.

Speaking on UK TV show 'This Morning' she said: ''We were filming the entrance and there was a huge splash and a guy jumped off the bridge.

''And because of our security guys we managed to get him out, but the most terrifying thing is how far he floated down the river.''

'The Rook' is based on the novel of the same name by Daniel O'Malley and follows Myfanwy Thomas (Emma Greenwell), a woman who finds herself at London's Millennium Bridge surrounded by dead bodies and no memory of how she came to be there - but it soon comes to light that Myfanwy is an agent of a British secret service called the Checquy and has supernatural abilities.

Joley plays Linda Farrier, the King in the Checquy and the '101 Dalmatians' star explained that she still isn't certain of how the supernatural spy drama will end.

She said: ''In the end, we shot two endings so I still don't know how it ends but it's very good you live in the moment.''

The miniseries was originally adapted by Stephenie Meyer and also stars Adrian Lester as Conrad Grantchester, the Queen in the Checquy and Olivia Munn as Monica Reed, an agent from the American BVA, a Checquy sister agency.