So it should come as little surprise that the pair are once again seemingly making jibes about each other following a joke from Hamilton about his Mercedes colleague's nationality and patriotism - or lack thereof.
The F1 roadshow will next head from Hamilton’s home turf at Silverstone to Hockenheim, where German-born Rosberg might expect similar levels of fervent local support.
But Hamilton has stoked the fires of the pair's topsy-turvy relationship by suggesting that it will not be the case given that Rosberg has a Finnish father - namely F1 legend Keke Rosberg - and he grew up and still lives in Monaco.
“To be honest, Nico has never actually been in Germany, so it is not really his home race,” said Hamilton.
"When I was racing in karting he didn’t stand with the grid girl next to a German flag ever. He always stood by Monaco.”
The 29-year-old was born in Wiesbaden, Germany, and his mother is German. His famous father Keke, however, is Finnish. Though Keke has a similarly confusing background, having been born in Sweden, married a German and lived in Monaco for years.
Rosberg has spent most of his life in Monaco and still lives in the Principality, which led Hamilton to further joke about his background and allegiances.
“I know he has grown up in Monaco, so Monaco is his hometown,” Hamilton insisted.
“He is German, Finnish, Monegasque or whatever, so he will get that support in Monaco and in Germany he has always had great support there.
"It is always good to beat others on their home turf,” he added, rather pointedly.
It seems rather ironic for Hamilton to be making fun of Rosberg in such fashion given that he has been far from patriotic in moving away from Britain to a tax-haven himself.
Equally, while his team-mate was making fun of him, Rosberg was showing his patriotism by posting the following message in support of Germany's efforts at the World Cup along with a picture.
"Thank you so much! That was mega fun! But feel sorry for all brazilians! (of course my bet was 7:1 for germany!)" he posted on Facebook.
When asked about Hamilton’s comments after testing at Silverstone on Tuesday, Rosberg said: "Anyone can judge however they want. What do you want me to say?"
He admitted he might not be as German as Hamilton is British “because I didn’t grow up in Germany, but I consider myself 100 per cent German.”
The Mercedes men have not always seen eye-to-eye, and frankly that's an understatement. It has been a hugely successful season for the team on the track, but off it relations have been less than harmonious.
A "best... photobomb... EVER!!!" caption to a happy social media-posted picture provided a swift U-turn in the pair's turbulent relationship with the title-chasing team, with Hamilton having said as recently as the Grand Prix in Monaco that him and Rosberg were 'not friends'.
That followed a string of tweets seemingly aimed at showing the world that the pair were, in fact, very good friends and just having fun on the F1 circuit.
— Speeddoctor F1 (@speedoctor1) June 12, 2014
— SPEED (@SPEED) June 3, 2014
Prior to that, Hamilton was left furious with his team-mate after Rosberg scuppered his chance of a crucial final qualifying lap at Monaco by stopping just off the track.
Rosberg claimed it was accidental as a result of braking too late; Hamilton, meanwhile, suggested that it had been done intentionally.
The pair's friendship goes back as far as their childhood days in karting, but the intensity of a championship battle with Mercedes clearly having the best car seems set to continue to cause divisions.
It had seemed as though all was back on track for Rosberg and Hamilton in their topsy-turvy dealings at Mercedes until these latest barbs: now the team and fans will have to hope that the collective success on the track converts to a long-term amicable relationship.
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- Lewis Hamilton
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