File picture: Francois Lenoir / Reuters.

Monza - Mystery surrounded Lewis Hamilton’s surprise absence from his media engagements ahead of the Italian Grand Prix.

Mercedes said the world champion’s absence was due to an "unavoidable personal commitment", but that vague explanation only started a guessing game about the specific reason.

Governing body the FIA were none the wiser other than to say Mercedes, which was tight-lipped in response to inquiries about its star driver, had told them he was not ill or injured.

Curiously, Hamilton posted videos on social media at the time he would usually have been in the Monza paddock.

However, he is expected to be back in the car for practice this morning.

Hamilton’s no-show followed Instagram posts in which he criticised reports from last weekend’s Belgian Grand Prix as "fake news".

Perhaps this was his boycott.

It was left to Ferrari to respond to Hamilton’s questioning of the legality of Sebastian Vettel’s Ferrari after the German won in Spa.

"Mercedes are not used to it," said Ferrari boss Maurizio Arrivabene. "We’re used to it. They’re not. So I told the boys to keep them under pressure."