Producers soon removedthe offending image from the press site, after fans began laughing at the sight of Robert, Earl of Grantham (Hugh Bonneville) and Lady Edith Crawley (Laura Carmichael) posing in period dress in front of an historically-inaccurate backdrop.
The tongue in cheek cast response is captioned with a link to charity WaterAid UK which works to provide people in need with safe water.
"After seeing the reaction the picture caused earlier this week, the cast and crew came up with the idea of turning some of this attention towards an issue around water that really matters," a statement on WaterAid's website reads.
Series five of the hit ITV drama is expected to return to UK screens in autumn, but a release date has not yet been announced.
There will be no water bottles cropping up once the new episodes air.
"While the water bottle is in the uncropped version of a publicity photograph, we can assure you that it will not be making an appearance on screen," an ITV spokesperson said.
