That Adorable White Nightgown!

As she fretted and frowned, Diane Cannon wore the most adorable white nightgown ~ it had huge puffy sleeves ~ it looked old-fashioned and billow and, I'll bet, it was a very comfortable thing to fret away in. I've searched and searched online but I've never really found anything that looked quite like it.

Anybody got any ideas on what brand it was or where she might have gotten it?

I realize this doesn't have much to do with the movie itself, but where else would I go to ask?