A rare comic featuring Superman’s first appearance in print has sold for millions on eBay.

Darren Adams sold his copy of the first “Action Comics” issue from 1938 featuring Superman for more than $3 million. Adams, who also owns Pristine Comics shop in Seattle, told the Washington Post he kept the comic a secret for a while.

"I actually held it for a few years – I was so excited about this book," Adams said. "Most books have a history … but this book was totally off the grid, and nobody knew about it till I made it known."

According to The Guardian, there are an estimated 100 comics of Adams’ first edition of “Action Comics” that were in circulation. However, the preservation of Adams' comic was almost near mint condition. The comic was authenticated by Certified Guaranty Company (CGC) and given a 9.0 out of 10 rating, which is extremely rare.

"The quality and preservation of this Action No 1 is astounding," Paul Litch, CGC primary grader, told The Guardian. "It is supple, the colours are deep and rich, and the quality of the white pages is amazing for a comic that is 76 years old."

It isn’t the first time an “Action Comics” issue has sold for a lot of money. The Guardian reports “Action Comics No 1” have sold anywhere from $86,000 to $1.5 million.

USA Today reports Adams is donated a small percentage of his $3 million sale to the Christopher & Dana Reeve Foundation. The organization has dedicated their time to helping people with spinal-cord injuries and paralysis.

Actor Christopher Reeve founded the organization after an accident left him a quadriplegic. Reeve was best know for portraying Superman in the 1978 film. The famous actor died in 2004.