A Japanese billionaire is putting the old adage “Money can’t buy happiness” to the test by giving away $9 million to his Twitter followers as part of a social experiment.

Yusaku Maezawa will dole out 1 million yen — or $9,000 — to 1,000 followers to see if the cash boosts their overall happiness.

The lucky recipients will be selected at random from those who retweeted his Jan. 1 post announcing the giveaway by midnight Jan. 7. The post received more than 4.1 million retweets.

“It’s a serious social experiment,” Maezawa, 44, said in a YouTube video announcing the stunt.

The impact of the windfall will be tracked through regular questionnaires and Maezawa is encouraging recipients to spend the money however they like.

Maezawa, who founded Japan’s largest online fashion mall, Zozotown, in 2004, is worth $2.7 billion, according to Forbes. He is set to become the first-ever private passenger to fly around the moon with Elon Musk’s SpaceX.

The fashion titan and art aficionado has made headlines before with his over-the-top purchases — including a $110 million Jean-Michel Basquiat painting in 2017.

Last January, Maezawa gave away 100 million yen, or about $914,000, to 100 Twitter users in a similar experiment, according to CNN. Each winner wound up taking home about $9,000 each.

His tweet last year became the most retweeted ever at the time, with 4.68 million retweets.

With Post wires