This lovely gown was designed by Margaret Furse, whose creations for Anne of the Thousand Days won an oscar for best costume design.
The gown was used again two years later for the excellent mini-series Elizabeth R, where it was slightly altered with a neck ruff to make it look more Elizabethan and some new trimming around the bodice.
The third time it was seen was in the film Mary, Queen of Scots, which also had costumes by Marget Furse. She used several of her creations from Anne of the Thousand Days in the production. The gown has been further altered, giving it a different, more elaborate neck ruff.
The gown made a fourth appearance, altered again, but looking very similar to its first use in Anne of the Thousand Days.