05/29/2006 AT 08:00 AM EDT
The annual Monaco Grand Prix Ball turned even grander just before midnight on Saturday when surprise guest Bono popped in to join the event's ball host Wyclef Jean for an impassioned duet of "Redemption Song."
Bono, who earlier in the day had sung on Formula One boss Flavio Briatore's yacht, Force Blue, arrived without warning, and with Jay Z in tow.
Jay Z, dressed in a white suit, kept silent during the performance, and within 10 minutes he and Bono were gone from the Salon des Etoiles, leaving thrilled partygoers to check out the photos on their digital cameras in disbelief.
To catch the big show, timing meant everything. "I missed Bono," mourned Kate Bosworth, another surprise guest who arrived about 20 minutes too late. Appearing with her new Superman costar Kevin Spacey, Bosworth told PEOPLE: "I wanted to come and be here earlier but I've just been working and working, mostly."
The Grand Prix Ball raised more than $1 million for Jean's charity, Yele Haiti, which promotes development in Jean's native country. Jean teared up as he spoke about Haiti, then joked to PEOPLE: "Just because I cried doesn't mean I'm going to be soft in the auction."
Some of the auction items fetched higher prices thanks to guest Petra Nemcova, who offered to pose with the winner of the Tahitian black pearl necklace worn by Jean pal Angelina Jolie when she received a humanitarian award from the U.N. in October 2005 (winning bid: $92,815).