"Although this has been authenticated by two separate authenticators I'm not totally convinced. The inscription looks more convincing than the signature (both the "Marilyn and Monroe look a bit atypical to me) so maybe I'm being…"
"Is there an address on the back of this envelop? Marilyn last lived in Van Nuys in 1943.
This could be her agent Johnny Hyde's secretary or one of her photographers, it looks a little like Bernard of Hollywoods autograph. Johnny Hyde was her…"
"This is a definite secretarial. That is, Fox Studios sent this out in response to a request.
Here is my Secretarials blog, although it is similar to a style on there, it does look like another hand I don't have an example of.