"She is Barbie come to life - she'd be great," she writes.
It seems it's not just the executives who think Robbie would be perfect for the part.
The actress herself was on board to play the real-life doll last May, according to an email from Hannah Minghella, co-president of production at Sony's Columbia Pictures division.
"Bugliari and JP pitched Margot the idea for Barbie and she loved it! She's free in October once she wraps Tarzan," Minghella writes.
As for Barbie's sidekick, Maggie, the executives play around with a few ideas including Kristen Wiig, Tina Fey, Amy Adams, Amy Schumer and Sandra Bullock.
In the exchange, Wiig is considered "a bit sad/pathetic" while Bullock is seen as potentially too old for the role.
"I like Amy Adams more than Wiig - more marketing bang there. Wiig is funny but can seem a bit sad/pathetic while Amy is entirely endearing," one Sony executive writes.
MacDonald's husband and fellow producer, Walter Parkes, says Robbie is the perfect Barbie but questioned whether Sandra Bullock would be too old to play Maggie.
"Are we sure Sandy isn't too old? Do we really believe she's on the cusp of 'losing her dream?'" he writes.
He suggested Amy Schumer as Maggie would be funny and also implies the leading ladies are not going to get paid very well for this film.|"And then there's the money," he writes.
"This is a concept movie. We shouldn't spend a bundle on the star. I'm not trying to undermine the idea of Sandy she's fantastic but I just want to ask the right questions."
- AAP