Letterman opens up about late-night rivalry

UNDATED (WHDH) -- In a new interview with Oprah talk show host David Letterman opened-up about his rivalry with tonight show host Jay Leno, and said that it did not start when Dave was passed over, for Johnny Carson's old seat.

Letterman said -- they were always friends before it happened.

Promotions for the interview haven't revealed Letterman's reason for the falling out with Leno.

The interview airs on Oprah's Next Chapter on January 6.