The one-off special will further explore Poppy's relationship with Arthur 'Fatboy' Chubb and how they spend Christmas Day together.
In an upcoming episode of the main show, viewers will see Poppy choose to be with Fatboy (Ricky Norwood) for Christmas rather than her family. The story then continues on the Red Button service.
Bright told Take It Easy: "Poppy spends the day with Fatboy. She is under pressure to go back to her family, but realises she doesn't want that. Her and Fatboy have a romantic day, but you don't see anything on screen [in the Christmas episode] because it is dominated by the Brannings.
"There will be an interactive section where viewers can press the red button and see a ten-minute film of how Poppy and Fatboy spent their day."
Discussing the pair's romance, the actress explained: "It's really sweet. I don't think Poppy or Fatboy realised they liked each other as they've been friends for a while. She's unsure at first because she doesn't want to ruin a friendship. She's also been unlucky in love, so she's a little bit wary.
"But I think she can trust Fatboy. I think the pair of them need love."