Ousted Nissan boss Carlos Ghosn's sudden appearance on Twitter on Wednesday was a surprise move by the businessman that perplexed people and sent journalists scrambling.

The first tweet from the @carlosghosn account read, "I'm getting ready to tell the truth about what's happening. Press conference on Thursday, April 11."

It did not specify a time or place.

Featuring a photo of a smiling, grey-haired Ghosn standing in front of a tree with seasonal cherry blossoms, the account initially lacked the blue tick mark to show it had been verified by the social network.

That left journalists unsure of its authenticity — particularly as the conditions of Ghosn's $9 million bail preclude him from using the internet.

Forty minutes later, when the blue tick appeared, the tweet swept across social media and the account's followers swelled to almost 20,000, from just a handful earlier.

Some of the replies appeared sympathetic to Ghosn, with others carrying photos of his now-famous exit from a Tokyo detention center last month.

"Stood right alongside you with #GiveGhosnBail. Looking forward to hearing your side," wrote one Twitter user with the name @highmileage.

Ghosn had also caught media off guard when he disguised himself in a workman's uniform, cap and face mask to try and give waiting reporters the slip on leaving the detention center after his release on bail. The architect of the Nissan and Renault global alliance was then pursued by media as he rode away in a small work van, a Suzuki, topped with a ladder.

Ghosn's dramatic fall from grace began with his arrest in November after getting off a private plane at Tokyo's Haneda Airport. He has since been charged with financial misconduct and aggravated breach of trust.

On Wednesday, the Yomiuri newspaper said Tokyo prosecutors will soon decide whether to prosecute Ghosn on further charges. A further arrest could jeopardize the planned news conference.

It remains unclear if Ghosn sent the tweet or it was sent on his behalf. His bail conditions allow him to access a computer at his lawyer's office but forbid him to use the internet.