Bonneville revealed the news at the Television and Radio Industry Club Awards in London on Tuesday, where Downton picked up the drama program of the year award.
The cast of the hit ITV period drama are currently filming the eight episodes that will comprise season six, with rumors still swirling that it will be the final season.
“We’ll do a ninth episode which will come out at Christmas,” said Bonneville when asked about the possibility of a Christmas special to bookend the sixth season.
The actor who plays Lord Grantham also teased some info on what fans can expect in the next season. “We’re in 1925, so the series has nudged on another six months, and Lady Rose has been on her honeymoon and she’s now moved to America,” he said.
“Tom Branston has gone to Boston, and some faces that we met towards the end of the fifth season may or may not be coming over the horizon to break or make the hearts of Lady Mary and Lady Edith and people like that.”
Bonneville was also asked if Shirley MacLaine or Paul Giamatti will reprise their roles in the new season, but he wasn’t letting anything slip: “I don’t know. I haven’t heard that one, but we’d all be delighted because we love having them. The guest artists we’ve had have been amazing and to have any of them back would be brilliant.”
Downton Abbey season six will air in the U.K. in the fall, with PBS yet to confirm when it will broadcast in the U.S.