Niki Lauda claims Lewis Hamilton trashed a hospitality room in Baku and subsequently lied about his relationship with Rosberg.
The Austrian, winner of three world championship titles and now non-executive chairman at Mercedes, made the admission on Red Bull's 'Sport & Talk' show for the Servus TV which was recorded last Friday as the Spielberg weekend got underway but broadcast last night (Monday).
Lauda, who was joined in the studio by Red Bull F1 Consultant Helmet Marko and Swiss journalist Roger Benoit, claimed that following a frustrating weekend in Baku, where the Briton, having crashed in qualifying, necessitating that he start the race from the fifth row, eventually finishing fifth, whilst Rosberg won and re-established a 24 point lead, was becoming sick to death at being asked about his relationship with the German.
According to Lauda, Hamilton subsequently made the claim that the relationship with Rosberg was "really, really good" in a bid to end the questions and also appear to be the 'peace maker' within the team.
"Lewis lied, simple as that," said Lauda. "He just said something. He wanted to be the peace maker in order to have peace."
Should there be any further clashes, said the Austrian - and this was recorded before the controversial events of Sunday - Hamilton would be able to claim that he was the peace maker and had tried his best to maintain calm within the team.
"You can rely upon it," Lauda said, "he is not a peace maker".
The Austrian then revealed that Hamilton was "so p***ed off" after qualifying in Baku that he wrecked his private hospitality room.
"He told me I couldn't come in because he was going to destroy everything," said Lauda. "He did it because he had crashed. This is how it was. "I was there, he smashed everything".
The Austrian, who will, in the wake of what happened in Austria probably regret having revealed quite so much to the 'Sport & Talk' audience, confirmed that Hamilton will have to pay for the damage to the room. "You can count on that," he said.