F1 will see a number of former foes partner up for the coming season.
Pierre Gasly has joined Esteban Ocon at Alpine to form an all-French combo, with much made of past fallouts between the new team-mates during their karting careers.
Haas' line-up comprises of Kevin Magnussen and the returning Nico Hulkenberg, who were involved in a famous scuffle at the 2017 Hungarian Grand Prix - although this has since been resolved.
So with the prospect of these duos becoming problematic and the intrigue over whether Red Bull will suffer from a hangover from Brazil last year - where Max Verstappen seemingly aired dirty laundry between himself and Sergio Perez in public - GPFans takes a look at some of the most heated team-mate rivalries in F1.
The duo only spent a season driving for Haas, but there were plenty of flashpoints.
Nikita Mazepin was convinced the team was more supportive of Mick Schumacher's efforts and sought to change the chassis of the underperforming VF-21 early in the year.
But the relationship between the drivers turned personal at the Azerbaijan Grand Prix when Mazepin almost ruined both drivers' races on the final lap, leading to Schumacher suggesting the Russian 'tried to kill us both'.
A similar incident at the Dutch Grand Prix, born out of qualifying frustrations, led to furious media interviews from both drivers before team principal Guenther Steiner stepped in.
Mazepin left ahead of last season after Russia invaded Ukraine, with Haas terminating his contract.
Two-time champion Fernando Alonso left Renault to join McLaren and partner rookie Lewis Hamilton for 2007 but things were not as easy for the Spaniard as he had perhaps planned.
Hamilton managed to get up to speed straight away and was a genuine championship contender after securing podiums in every race until the European Grand Prix at the Nürburgring.
But at the Hungarian Grand Prix, frustrations over team orders during qualifying led to Alonso infamously failing to leave his pit box when requested after a stop in Q3, leaving Hamilton with insufficient time to set a new fastest lap.
Alonso took pole but was demoted, elevating Hamilton onto the front row with Kimi Raikkonen.
Tensions between the pair have remained since, not least at least season's Belgian Grand Prix.
Nigel Mansell and Nelson Piquet - Williams 1986-1987
When Nelson Piquet joined Williams in 1986, no one could predict the fiery nature of the relationship that would be created with Nigel Mansell.
On track, the pair put on a show with numerous scintillating battles - not least when Mansell tracked down Piquet at Silverstone in 1987 and made a sensational dummy-switch pass into Stowe corner.
But there were issues between the drivers, with one example being Piquet had discovered the benefits of a new Williams differential, keeping the advantages a secret from his team-mate.
After switching to Lotus, Piquet labelled the British driver an "uneducated blockhead" and also levelled an insult at Mansell's wife.
The duo have since reconciled, but their rivalry as team-mates has become the stuff of legend.
Gilles Villeneuve and Didier Pironi - Ferrari 1981-1982
Gilles Villeneuve was joined at Ferrari by Didier Pironi in 1981 but the relationship soured in their second year together.
At Imola, with both of the Scuderia's cars in the lead, a board ordered the team-mates to go slow, though Villeneuve read this as an order to hold station.
When Pironi overtook Villeneuve on the final lap, the Canadian vowed to never speak to his team-mate again.
The promise was kept in tragic circumstances when Villeneuve was killed during qualifying at the next event at Zolder.
Lewis Hamilton and Nico Rosberg - Mercedes 2013-2016
Former team-mates and best friends in karting, Nico Rosberg was joined by Hamilton at Mercedes in 2013.
The following year would see the duo dominate the championship at the beginning of the Silver Arrows' monopoly over the sport.
The famous 'duel in the desert' in Bahrain gave us a taste of what would unfold, but numerous incidents across the three years left the relationship in tatters, splitting the team in two.
A 'mistake' in Monaco qualifying and contact at the Belgian Grand Prix in 2014 was just the beginning, with further incidents following - especially in Rosberg's title-winning season in 2016, where crashes in Spain and Austria reignited the discord.
Rosberg retired at the end of the year before Hamilton went on to forge a new relationship with 'best team-mate' Valtteri Bottas.
Multi-21 will always dominate the bitter feud between Sebastian Vettel and Mark Webber.
The duo never saw eye-to-eye at Red Bull, with the German often being protected by the team in the eyes of Australian Webber.
There was the spare front-wing debacle at Silverstone in 2010 where Vettel was given Webber's upgraded part when his had failed early in the weekend.
Webber won the race to prove a point, prompting his caustic remark - "Not bad for a number two driver". This fiasco came only after the duo had collided in a battle for the lead in Turkey.
But Multi-21 in Malaysia 2013 was the final straw, before Webber retired from F1 at the end of the year.
The most famous of team-mate rivalries, Ayrton Senna and Alain Prost just rubbed one another up the wrong way.
Brazilian superstar Senna joined McLaren from Lotus to team up with 'The Professor' in a dominant driver pairing.
But relations were always frosty and with Senna chasing Prost to stay in the fight for the 1989 title before the trip to Adelaide, the duo clashed at the final chicane in an iconic moment in F1 history.
Senna was disqualified for rejoining the track by cutting the chicane, and after McLaren protested to reinstate the Brazilian, Prost opted to join Ferrari for 1990.
Despite being in opposing teams, the simmering rivalry sparked into life in Japan again that year with a collision at the very first corner of the showdown.
Senna labelled Prost "a coward"; Prost called Senna "disgusting". It was a pairing full of drama and tension barely recreated by any that have since followed.