Johnny Mathis has slammed Frank Sinatra and Barbra Streisand in a new interview, insisting both stars made his life hell when he worked with them.

The WHEN A CHILD IS BORN singer found Sinatra to be aloof and critical of his crooner rival, while Streisand was a diva who insisted on re-recording duets.

Mathis says of the late Sinatra, "He was very sure of himself. He once said of me, 'Oh, yeah, he sings good, but who wants to listen to that s**t?'"

Meanwhile, of Streisand, he states, "She was very difficult. It took a monumental amount of time."