We'd love to be a fly on the wall (or "The Fly," if you must) at the Paris Fashion Week event that had rock superstars Paul McCartney and Bono seated next to each other on Monday.

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Paul McCartney, left, and Bono in Paris on Monday.

The former Beatle and the U2 frontman turned up in the front row for Stella McCartney's Fall/Winter 2013 Ready-To-Wear show. What do you think the two men chatted about?

We chuckled at the prospect of Bono bumbling through a list of questions à la Chris Farley in the memorable "Saturday Night Live" skit with the late comic as a nervous talk-show host.

Bono: "You remember when ... remember when you were with the Beatles?"

McCartney: "Sure."

Bono: "That was awesome."

McCartney: "Yeah it was."

Getty Images file

Bono.

Bono made a surprise appearance on Sunday night at Bemelmans Bar at the Carlyle Hotel in New York, where he joined singer Jim Caruso and pianist Billy Stritch onstage for a handful of standards, the Huffington Post reports.

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"Bono walked in. It was impossible not to recognize the guy – the glasses alone gave him away!” Caruso recalled to the Post. "They were seated in the corner, where they rocked, bopped, swayed and snapped. He kept giving me the thumbs-up when he'd like a tune and singing along quietly."

Stritch and Caruso were performing tunes from the Great American Songbook, a set of classic songs that the U2 frontman knows well. Before Bono left, he headed right for the stage and joined in harmonies to "I've Got You Under My Skin," a track he recorded with Frank Sinatra in 1993.

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"The room was stopped cold," Caruso said. "Just another miraculous Bemelmans moment! After the last note was crooned, Bono flew out the door, waving to everyone. Billy looked at me and said dryly, 'Well ... that happened!'"

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Larry Marano / Getty Images file

Bono

Despite numerous reports that the Facebook IPO would make him the world's richest musician, U2 lead singer Bono said on Friday that wasn't true.

"Contrary to reports, I am not at this point a billionaire, or going to be richer than any Beatle," Bono told Andrea Mitchell on msnbc TV. (Read the transcript of his interview.)

A report in British music magazine NME on Thursday made the claim that Facebook's IPO would push Bono's wealth past that of former Beatle Paul McCartney, who reportedly is the richest rock star in the world, with a fortune of more than a billion dollars.

Bono is part of a private equity firm, Elevation Partners, which reportedly owns 2.3 percent of Facebook.

The firm’s stake in Facebook is worth about $1.4 billion, but a spokesman for Elevation said “the vast majority” of the money controlled by the firm is invested on behalf of pension funds, endowments and institutions, not individuals.

 Rolling Stone reported that Bono has said his returns would go towards his charity work in Africa.

Facebook stock opened at $38 on Friday, jumped as high as $43, then fell back to close just pennies above its opening price.

Speaking with Mitchell, Bono went on to praise Facebook, saying "it's a technology that brings people together," and pointing out that the social network played a role in North Africa's so-called Arab Spring. But he agreed with Mitchell that he wasn't sure if Facebook readers were taking note of the site's ads, and said he'd leave the business model to Facebook's employees.

All things considered, it didn't seem to bother the musician, who told Mitchell that his chosen career has always made him feel rich. "I felt rich when I was 20 years old and my wife was paying my bills," he said. "You know, just being in a band."

Editor’s note: Earlier on Friday, TODAY.com published a story, provided by The Hollywood Reporter, reporting that Facebook’s IPO would make U2 singer Bono the richest musician in the world.

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