Square and Twitter chief executive officer Jack Dorsey's first-ever tweet, offered for sale as a non-fungible token (NFT), was sold for just over $2.5 million or 1,630.58 Ethereum (ETH) based on the crypto's price at the time of sale, The Straits Times reported Tuesday.

An NFT is a kind of unique virtual asset that has grown in popularity so far this year. Ownership of these assets is recorded on blockchain technology.

But a person can't exchange one NFT for another as they would with dollars or other assets. Each NFT acts as a collector's item that can't be duplicated, making them rare by design.

Dorsey's tweet, "just setting up my twttr", was first published on March 21, 2006 and it received bids as high as $88,888 within minutes. It was listed for sale as an NFT on March 6 this year.

The winning bidder was Sina Estavi, chief executive officer of Bridge Oracle, a Malaysia-based blockchain company.

The NFT was sold via auction on a platform known as Valuables, which is owned by Cent, a U.S.-based company.

Cent chief executive Cameron Hejazi said his platform enables people to show support for a tweet that goes beyond the current options to like, comment and retweet.

Dorsey said earlier he plans to convert all the proceeds of the auction to Bitcoin (BTC) and send the funds to a charitable group called Give Directly's Africa Response, which provides monetary aid to impoverished families in Rwanda, Kenya, Liberia and Malawai.

"This is not just a tweet ... I think years later people will realize the true value of this tweet, like the Mona Lisa painting," The Wall Street Journal quoted Estavi as commenting on Twitter.

Meanwhile, a tweet by Tesla CEO Elon Musk attracted a bid of $1.12 million by Estavi as well. The tweet featured the billionaire's announcement of selling a song on NFT's as a digital property.

Musk later changed his mind about selling the song, which also gained interest from the artist Beeple who offered him $69 million for the NFT.