Nostalgic 30-somethings yearning for the self-lacing Nike sneakers Marty McFly wore in "Back to the Future II" may not have a long wait in purchasing a pair of their own.

Nike got a head start on Oct. 21, 2015 Back to the Future Day festivities by sending McFly, played by Michael J. Fox, a cryptic tweet that simply said "see you tomorrow." Wednesday morning, the Oregon-based company told Mashable a pair of self-lacing Nike Mags - the indelibly futuristic shoes Fox wore atop a hoverboard - were in New York City; the claim was verified by CNBC's Sarah Eisen.

The letter I received from Tinker today. Thanks @Nike pic.twitter.com/UIolXrkUVC

— Michael J. Fox (@realmikefox) October 21, 2015

Soon, the not-so-secret secret was out. Fox tweeted a letter he received from iconic Nike designer Tinker Hatfield, who, in January, teased at such an announcement later in 2015. The handwritten letter, partially hidden behind a penned sketch of Fox with holding up a Mag, concluded with Hatfield saying "if my calculations are correct...your pair should be with you shortly."

Release date

The Michael J. Fox Foundation captioned a picture of Fox wearing a Mag with "This is real. This is today. Coming spring 2016," presumably indicating the shin-high sneakers would be available to the public next year.

Nike confirmed as much in a press release published on Wednesday.

Price estimate

Estimated pricing hasn't been released, but it it's anywhere near what eBay users payed for a similar pair in 2011, prepare to transfer funds over from your savings account.

Nike's first take at the Mags came a year after they applied for a patent the advanced, self-lacing shoes needed. The company made a very limited supply - 1,500 - but sold every one through an eBay auction that netted Fox's foundation about $5 million. In his letter to Fox, Hatfield said the 2015 version would "raise even more than the $9.4 million collected in 2011 and contribute in some way to eliminating Parkinson's Disease in our lifetime!"

Each pair sold for an average between $3,000 and $7,000, based on whichever estimate you prefer. That was four years ago, well before Nike installed an ankle-clinching system that seamlessly tightens and loosens laces with the push of a button. The price can only go up from here.

Where to get a pair

Like their predecessor, the new Nike Mag won't be available for retail purchase.

"The 2015 Nike Mag is a limited edition release," Nike's statement read. "It will only be available via auction, with all proceeds going to the Michael J. Fox Foundation for Parkinson's Research." Specific date and auction website details weren't given.

How to make your own

Purchasing thousand-dollar sneakers won't be on most people's priority list, regardless of power laces, neon lights, and how they enliven childhood memories. That's why DIY blogger Blake Bevin went about making his own pair, only his idea arose five years ago just as the original Air Mags came out.

Bevin used a Nike High Top for his version, installing micro-controlled sensors to read pressure placed on each foot. "Operation is quite simple- step into the shoe and a force sensor reads the pressure of your foot and activates two servo motors, which apply tension to the laces, tightening the shoe. A touch switch reverses the servos," Bevin wrote on the website Instructables.

Based on his instructions, the most pertinent parts are a high top with a lot of padding, an Arduino microcontroller, motor shield, servo motors, sheet metal, and LED, among a few other things that could be found around the house.

They may not be Mags, but making your own set of "Back to the Future" sneakers may be the next best thing.