Nico Rosberg messaged Lewis Hamilton to inform him of his decision to retire from Formula One before making the announcement public.

The new Formula One world champion surprisingly revealed he was to call it quits on Friday, just five days after clinching a maiden title ahead of Mercedes team-mate Hamilton at the season-ending grand prix in Abu Dhabi.

The duo have seen their childhood friendship tested by a fierce battle for supremacy in F1 in recent years and Rosberg admitted before the final race that it was difficult for them to have a close relationship.

However, Rosberg says that he ensured Hamilton knew of his retirement plans out of respect.

"I informed Lewis myself because it's the right way to do it," he said at the FIA Prize Giving in Vienna.

"We've had such a battle and so many moments fighting each other so I thought it was correct to let him know of my decision.

"I had to do it a bit quick, so I sent Lewis a message. Maybe we'll have a discussion about it [in person].

"It has been so short notice because the priority was to let the team know as quickly as possible so that was a bit of a compromise for me, that I wasn't able to do a perfect job in taking enough time to notify everybody that was close to me."

Rosberg competed in 206 grands prix during his career, winning 23 races and standing on the podium 57 times.

And the German insists there is no chance of him reversing his decision.

He added: "Definitely not. [I am] finished. Done. End of story."