Did Karl Barth summarize his life message as “Jesus Loves Me, This I Know….?”

Roger Olson recalls a popular illustration:

According to the story, Karl Barth was fielding questions from the audience after a lecture in Rockefeller Chapel on the campus of the University Chicago in 1962. A student stood and asked him if he could summarize his life’s work in theology in one sentence. According to the story a gasp went up from the audience–responding to the student’s perceived audaciousness. Also, according to the story, Barth didn’t skip a beat. He said (paraphrasing) “Yes. In the words of a song I learned at my mother’s knee: ‘Jesus loves me, this I know, for the Bible tells me so’.”

But did it really happen?

Can anyone help verify whether this is legend or really happened? Anybody know someone who was there? Pop over to Karl Barth’s “Jesus Loves Me, This I Know….” Answer: Can Anyone Verify It? and share any insight you may have.