One of the earliest is Charlie Chaplin's THE MASQUERADER.  You may also want
to look at:  BLONDIE GOES TO RIO, and there's an Andy Hardy comedy in which
Mickey Rooney poses as Carmen Miranda.
 
Billy Wilder uses the device later in "1,2,3", and of course by the 1970's it
becomes quite commonplace.
 
----
To signoff SCREEN-L, e-mail [log in to unmask] and put SIGNOFF SCREEN-L
in the message.  Problems?  Contact [log in to unmask]