There are a few things that are interesting about this gown. First, both appearances of it on screen were in in 2008. The gown was designed by Sandy Powell on a tight budget for the production The Other Boleyn Girl. She mentioned how most productions rent costumes for extras, but she was unable to do so because every Tudor and Elizabethan costume had been rented out for the filming of the first season of The Tudors, and she was therefore forced to make costumes for the entire cast. You can read a great article about it here.
Once production of the film ended, the second season of The Tudors began, and they soon snatched up a few pieces from The Other Boleyn Girl, which had now become available for use.