Nike

How much is a pair of real-life Marty McFlys from "Back to the Future II" worth? To Tinie Tempah, the answer is $37,500. That's how much the British rapper paid for the Nike sneaks during a live auction Wednesday night in Los Angeles, TMZ reports.

"It was a total spur-of-the-moment decision," the rapper told the publication. "I was really touched in the moment by the presentation and next thing I knew I owned these iconic sneakers."

Anyone with deep pockets can still bid on one of 1,500 pairs of Nike's new Air Mag 2015 sneakers up for auction on eBay's Fashion Vault. Proceeds from the 10-day auction will go to the Michael J. Fox Foundation for Parkinson's research.

The man behind the famed Marty McFly character, actor Michael J. Fox, went on the "Late Show with David Letterman" last night to show off the rechargeable kicks (see the vid below). They look like the originals, but sadly don't sport power laces.

Most of the shoes being auctioned haven't come close to the $37,500 price tag yet and are instead going for $4,000 to $11,000.

Screenshot by Boonsri Dickinson

As for why the rapper spent so much on the shoes? The British rapper is a sneaker collector, apparently, as well as a big "Back to the Future" fan. Perhaps we'll be seeing his new kicks in his next music video.