Brad Pitt and Angelina Jolie enjoy romantic dates in a hotel Jacuzzi.

The couple and their six children are currently staying at the Claremont Hotel in Berkeley, California, while the actor works on his next movie 'Moneyball' and staff have treated their stay like a "military operation".

A source said: "We approached the arrival of Angelina Jolie and Brad Pitt -- plus their kids and entourage -- as if it was a military operation."

According to the insider, the couple regularly book the hotel's spa facilities for personal use in order to have "romantic date nights", while they are also happy to pay to have "Under repair" signs posted on the swimming pool so it can be closed for their kids to splash around in peace.

In addition, despite the couple rarely seen in the public areas of the hotel, staff were reportedly ordered to remove any magazines with them on the cover from the lobby newsstand.

The source told the Chicago Sun-Times newspaper: ''That pretty much cleaned out our celebrity magazines since Brad and Angie are on the cover of those magazines almost every week!''

Brad, Angelina, their family and entourage occupy a whole floor of the building, and have had "anti-paparazzi" reflective material placed on all of the windows to maintain their privacy.

In addition, the source reports that the 'Changeling' actress - who is a United Nations Goodwill Ambassador - has been spending a large amount of her free time in the library at the University of California' Berkeley campus doing research for a book about the international refugee crisis.