On July 18, 1999 — On Yogi Berra Day at Yankee Stadium, David Cone becomes the 16th pitcher in major league history and the third Yankee to toss a perfect game, beating the Expos, 6 – 0. In pre-game ceremonies, Don Larsen throws out the ceremonial first pitch to Yogi, commemorating his 1956 World Series perfect game. Coincidentally, these are the only two perfect games ever pitched in interleague games.

Source:
Baseball Reference July 18