The two stars, who were bitter rivals on and off the show, hugged and sobbed as they reconciled at Los Angeles restaurant Stk on Tuesday night.
According to reports, producers at U.S. news show Extra brought the pair together after both expressed a desire to end their war of words - but neither was told the other was going to be at Stk.
Conrad was celebrating the success of her runway show at Los Angeles Fashion Week when she spotted Montag and her boyfriend Spencer Pratt sitting at the restaurant's bar.
Montag asked Conrad's minders if she could congratulate her former friend on her new designs and the two women embraced.
Montag later thanked Extra's producers for bringing the two together.