US singer Christina Aguilera is set to perform a private concert in Spain after a devoted fan paid to fly her over.

The unnamed man is paying a reported 2.4 million euros for the performance.

And with Aguilera playing just four songs, it works out at more than half a million euros each.

However, the date and venue of the appearance by the singer – whose hits include Genie in a Bottle, Beautiful and Dirty – remain a closely guarded secret.

News of the arrangement was first broken by infamous Hollywood gossip blogger Perez Hilton.