AceShowbiz -

"Downton Abbey" latest effort to hype up its upcoming season 5 is ruined by a historical mistake. One of the newly released promotional photos from the next installment includes a misplaced modern convenience.

The gaffe is visible in a photo featuring Robert Crawley (Hugh Bonneville) and Lady Edith (Laura Carmichael). Dressing in 1920s outfits, they stand in front of a grand marble fireplace but someone apparently left a plastic water bottle in the background.

Plastic bottles weren't widely used in the U.K. until the early 1960s. This blunder certainly hurts the show's reputation which has been known for its authentic period props. The picture has been removed from the show's official Facebook and Instagram pages, but it has spread online.

The historical error aside, other new photos feature familiar faces including Lady Mary (Michelle Dockery) with her suitor Lord Gillingham (Tom Cullen) and her sister Lady Sybil's widower Tom Branson (Allen Leech), Isobel Crawley (Penelope Wilton), Mr. Bates (Brendan Coyle) and Anna Bates (Joanne Froggatt). New character Simon Bricker, played by Richard E. Grant, is seen in another image with Cora Crawley (Elizabeth McGovern).

"Downton Abbey" season 5 is scheduled to premiere January 4, 2015 at 9 P.M. ET/PT on PBS, months after it airs in the U.K. New additions to the cast include Anna Chancellor as Dowager Lady Anstruther, Sue Johnston as Lady's Maid to Dowager Countess of Grantham, twins Oliver Barker and Zac Barker as Master George Crawley, as well as Fifi Hart Miss Sybbie Branson.