In an upcoming "60 Minutes" special, Mike Wallace acknowledges that he tried to commit suicide two decades ago.

The 88-year-old Wallace, who is retiring from full-time correspondent duties on the TV news magazine, is the subject of a retrospective, "I'm Mike Wallace," that airs Sunday evening on the CBS network.

Wallace has openly talked about problems with depression, but never said publicly that it got to the point of a suicide attempt. But when "60 Minutes" colleague Morley Safer questions him about it, Wallace says he did once attempt it.

"I don't know why the hell you asked me that question, because other people have," Wallace says. "It's the first time I have answered it honestly."

Wallace vaguely relates the circumstances behind the attempt, which involved taking an excess of pills, but says that the 20 years since "have been the best in my life."

In the tribute, Wallace also reflects on various memorable interviews, among them, his famous prodding of Barbra Streisand in 1991. He says "that was mean," and makes an on-camera apology to the singer.