04/23/2007 at 09:00 AM EDT
Talk about an expensive birthday present: A Russian billionaire forked over $2 million for Jennifer Lopez to perform at a joint birthday party for himself and his wife Saturday night, sources tell PEOPLE.
Lopez's 40-minute set – which included such hits as "Jenny From the Block" – cost 35-year-old Andrei Melnichenko $1.2 million.
He paid another $800,000 to fly the singer, her husband Marc Anthony and their entourage from the U.S. to his 27-acre estate in Surrey, England, and put them up at the Mandarin Oriental in London.
"I can confirm that a very high-profile American singer performed at a private party in Surrey," Melnichenko's spokesman, Brian MacLaurin, tells PEOPLE.
Sixty guests, including Russian and Serbian tycoons, attended the bash for Melnichenko and his 30-year-old wife, former model Aleksandra Nikolic Melnichenko.
Melnichenko, who is worth $5 billion, according to his spokesman, made his fortune founding MDM Bank. He's no stranger to lavish spectacle: He paid Christina Aguilera $4 million to sing at his 2005 wedding in the south of France.
But even with her own generous payday, Lopez didn't hit London's tony Bond Street – instead, she and Anthony spent an hour on Saturday shopping at the fashionista's bargain favorite, Topshop.