Michelle Trachtenberg

National Geographic has released the first photo of Michelle Trachtenberg in Killing Kennedy and the actress looks very different.

Photos: Look who's all grown-up!

Trachtenberg, who rose to fame playing precocious child detective Harriet the Spy and Buffy's whiny younger sister Dawn, is all grown-up in the anticipated Nat Geo telepic, in which she plays Marina Oswald.

The Russian-born Oswald was the wife of John F. Kennedy's (Rob Lowe) assassin Lee Harvey Oswald (Will Rothhaar).

Check out Rob Lowe and more stars who don't look their age

Killing Kennedy
chronicles the final years of Kennedy and Oswald and will debut in November.

Check out the first photos of Lowe as Kennedy and Ginnifer Goodwin as Jacqueline Kennedy here.