Naomi Osaka enters NFT space with sister Mari

If tennis fans haven't jumped on the non-fungible token (NFT) train yet, Naomi Osaka has given them a reason to get into the game. The four-time major champion announced on Friday that she and sister Mari have been working on creating, not just any NFT, but something with a little twist for collectors.

Naomi's older sister has shared her artwork and passion for drawing over the years, and drew five cards being auctioned, including one "open raffle" card for "The Colors of Naomi Osaka" collection.

"As lovers, creators, and curators of art since we were young, Mari and I are very excited to formally enter the world of art through NFTs. We wanted to do something a little bit different and more personal, so I asked my sister to create these pieces with me to offer something unique and special to fans and collectors from around the world," Osaka wrote on Instagram.

Each of the five pieces being auctioned already have bids. Let's just say fans will have to spend a pretty penny on Osaka's first NFT drop.

Currently, the lowest bid is $25, 500(!)

Though the bidding price is steep, there is hope of snagging one by entering the $5 raffle. One lucky winner will receive the "Finding What Was Lost" card, along with a custom Nike package from the sisters.

The collection offers a more personalized and intimate burst of expression. Mari's use of colors also aims to "showcase the many shades of Naomi's personality and character."

If fans do decide to drop a little cash on these gems and win, they should also expect a signed Yonex racquet from the 23-year-old star to be delivered to their doorstep.

The auction and raffle close Friday, April 23.