09/03/2013 at 07:00 AM EDT
Melanie Griffith is 50 shades of delighted!
The actress spoke out Monday of her joy after author E L James revealed that Griffith and Don Johnson's daughter Dakota Johnson has been cast as Anastasia
in the movie version of Fifty Shades of Grey
"My beautiful child Dakota has been chosen to play Anna Steele in 50 Shades," Griffith, 56, wrote on Twitter
. "Look out world! Here she comes!!! #proudmama."
Some Fifty Shades
fans were less ecstatic at the casting news, largely because Johnson, 23, and Charlie Hunnam, 33, cast as Christian Grey, are relative unknowns. She was on the short-lived sitcom Ben and Kate
, while he stars on Sons of Anarchy
But Dana Brunetti, one of the movie's producers, defended the choices.
"There is a lot that goes into casting that isn't just looks. Talent, availability, their desire to do it, chemistry with other actor, etc," he wrote
. "So if your favorite wasn't cast, then it is most likely due to something on that list. Keep that in mind while hating and keep perspective."
"Auditions were stunning, incredible chemistry," added another producer,
Michael De Luca.
The movie, based on the first book in James's erotic trilogy, is set for an August 2014 release.
Additional reporting by K.C. Baker