Arsenal have completed the signing of Leandro Trossard from Brighton in a deal that would eventually be worth £27million.
Mikel Arteta has been eager to strengthen his attacking options as the Gunners pursue a first Premier League title since 2004 and Belgium international Trossard, 28, fits the bill.
Brighton will receive a guaranteed figure of around £20m with the remaining £7m made up of achievable incentives.
Arsenal have completed the signing of Brighton forward Leandro Trossard in a £27million deal
Trossard's arrival will bolster Mikel Arteta's attacking options ahead of the title run-in
Trossard could be in the Arsenal squad to face Manchester United in a pivotal clash at the Emirates Stadium on Sunday.
Although he signed his deal before midday on Friday, there was no confirmation over his registration before the deadline that would allow him to compete against the Red Devils - although it may appear likely.
Sportsmail understands that Trossard can expect to double his current salary to around £90,000-a-week at the Emirates Stadium.
Arsenal wanted to sign the Ukraine winger Mykhailo Mudryk this month but they were gazumped by London rivals Chelsea, who paid Shakhtar Donetsk an initial £62m with a possible £26m in add-ons.
The Gunners, who enjoy a five-point advantage over Manchester City at the top of the Premier League with a game in hand, moved quickly to identify other targets, including Trossard.
Chelsea announced the signing of Mykhailo Mudryk from Shakhtar Donetsk last Sunday
Trossard in action for Brighton against his new club Arsenal on New Year's Eve
The Belgian has been training alone at Brighton amid an ongoing stand-off with manager Roberto De Zerbi.
His deal at the Amex Stadium was set to expire in the summer, although Brighton retained an option to extend it a further 12 months.
But he was axed from the squad that beat Liverpool 3-0 last Saturday and continued to be exiled from the first-team this week.
Trossard, who also attracted attention from Tottenham, made clear he wanted to leave the south coast club and has now got his wish.
Trossard had been axed from the first-team squad at Brighton after a fall-out with De Zerbi
De Zerbi and Trossard had not seen eye to eye since the Italian coach took over
It remains to be seen, however, how Trossard takes to what is likely to be - at least from the start - a peripheral role under Arteta, whose starting XI is largely settled.
But his Premier League experience will come as a major boost to Arsenal's hopes of winning the title given he will not need time to adapt to a new division.
His versatility is a major attraction to Arteta, with Trossard able to play on either flank or as No 10.
Trossard featured in all three of Belgium's matches at the World Cup and was selected ahead of Eden Hazard in Roberto Martinez's starting XI in the crucial final group game against Croatia.
Trossard in action for Belgium against Croatia during the group stages of the World Cup
Sportsmail revealed the stand-off between Trossard and De Zerbi.
The coach said last week: 'The last training session before the Middlesbrough game (last Saturday) when he understood he didn't play, he left the session without saying anything to me. And it's not good.
'The Monday after, I spoke with him and I explained this attitude, this behaviour, I don't like. He knows very well that if he wants to play with Brighton with me, he has to work hard, he has to run, he has to be in the right way because we are not a big team such as Real Madrid or Barcelona, we are Brighton and we need players who work like the others who stay in Brighton.
'I don't know what is the problem. I want to be clear, I am open with him to take a step back and listen to him but he has to understand with me, I want only players who work hard and play for the team 100 per cent.'
The episode then took an unexpected twist when Trossard's representative issued a statement indicating the forward wants to leave and that De Zerbi had given his client the cold shoulder following a training ground incident involving another player.
The Belgian scored 25 goals in 121 games for Brighton after signing from Gent in 2019
Agent Comhair Josy said: 'Before Leandro left for Qatar, Brighton intended to (re)-sign Leandro.
'This did not happen as the parties did not come to an agreement. Leandro has also indicated that he is ready for his next step.
'After the World Cup there was an altercation between Leandro and another player at the training about a trivial matter. Since then, the trainer no longer speaks to Leandro, which is obviously not conducive to the atmosphere, as well as performance.
'Leandro still had a starting place against Southampton and Arsenal, but against Everton he was on the bench. He was also not included in the five substitutions that took place at the time, and this without any explanation.
'In the run-up to the match against Middlesbrough for the FA Cup, Leandro had already indicated twice that he had problems with his calf.
'This was the reason why he stopped training. This was, incidentally, in consultation with the medical staff.
'Leandro has had to learn through the physical trainer that he has to train separately. Last Monday, the trainer indicated that he no longer wanted to see him, a trainer who has not communicated directly with his player for four weeks is really incomprehensible.
'It is also the trainer who has indicated several times that a transfer is the most convenient solution.
'It is therefore important that Brighton co-operates in a potential transfer and acts benevolently, which is beneficial to both parties.'
