Keith Olbermann, who was fired by Al Gore's Current TV two days ago, stopped by to chat with David Letterman on Tuesday's Late Show and admitted, "I screwed up. I screwed up really big on this. Let's just start there."

He explained, "I thought we could do this. It's my fault that it didn't succeed in the sense that I didn't think the whole thing through. I didn't say, 'You know, if you buy a $10 million chandelier, you should have a house to put it in. Just walking around with a $10 million chandelier isn't going to do anybody a lot of good, and it's not going to do any good to the chandelier.' And then it turned out we didn't have a lot to put the house on to put the chandelier in, or a building permit, and I, I should have known that. And it is, it is my fault at heart."

"You're the chandelier?" Letterman asked to audience laughter.

"I'm the chandelier," Olbermann replied. "You are always pointing out how big my head is, so I think it's a suitable analogy."

Letterman asked if it felt as though he had made a mistake the minute he signed on to Current nine months ago.

"It did," Olbermann said. "And we even joked about it, if you recall, last September when I came out and did a Top Ten List…"

Letterman played the tape of it - Top Ten Reasons to Watch the New 'Countdown with Keith Olbermann' - with Olberman reading No. 2: "Better watch now because things could go wrong in a hurry."