The singer will play the prestigious Sunday afternoon slot at the Obelisk Arena at 1pm on July 15.
The performance has been pushed back an hour from its traditional midday slot to allow festival-goers to watch Lang Lang at the Waterfront Stage at noon.
Wainwright releases his seventh studio album Out of the Game, produced by Mark Ronson, on May 1.
He recently announced a series of UK tour dates, kicking off at Oxford's New Theatre on November 16 and finishing at Glasgow's O2 Academy on December 14.
Latitude Festival takes place at Henham Park, Southwold, Suffolk from July 12 to July 15. Tickets are on sale now.
Elbow, Paul Weller, and Bon Iver will headline the event, while Lana Del Rey and Ben Howard will also perform over the weekend.
Watch Rufus Wainwright's video for 'Out Of The Game' below: