(written from a Production point of view)
Michelle Chateau (born 1961; age ~60) is an actress who appeared as a nun in Star Trek IV: The Voyage Home. She received no credit for her appearance and described her part as a "silent bit" part. 
Beside her appearance in Star Trek IV, Chateau had a lead role in the San Francisco Art Institute film She Chase and was featured in episodes of Crazy Like a Fox and Partners in Crime. She also appeared in commercials for Becks Beer and Macy's California.
Chateau worked as certified makeup artist and instructor for Clarins in North California and Nevada and as model for several runway shows, print work, and hair shows. Today, she lives in Portland, Oregon.