Arsenal have acquired their first important signing of the transfer window after completing a £30 million plus add-ons deal for Porto midfielder Fabio Vieira.
The Portuguese club confirmed in a statement that the 22-year-old was leaving to join Arsenal.
Vieira had cut short his holiday in Mykonos to have a medical and sign for the Gunners.
Vieira had been on holiday in Mykonos but has arrived in London after abandoning his downtime.
Mikel Arteta is keen to bolster his squad and Arsenal are believed to have offered Porto an initial fee of around £30 million before add-ons, which O Jogo reported are easily achievable.
Vieira, a versatile attacking midfielder, came through the youth ranks at Porto and helped them win the Portuguese title last season.
The Portugal Under-21 international enjoyed a breakthrough year last season, amassing six goals and 14 assists in 27 league appearances for Porto to help the club claim a 30th league title.
No Arsenal player was involved in as many goals during the 2021-22 Premier League campaign and Vieira would join a promising group of creative talents including Emile Smith Rowe, Martin Odegaard and Bukayo Saka.
Arteta has already signed teenage forward Marquinhos but the arrival of Vieira would be a huge boost, given Arsenal's Big Six rivals have moved rapidly to bolster in key areas.
The Spaniard also remains keen on signing long-term target Youri Tielemans but Arsenal and Leicester are yet to agree a fee for the 25-year-old Belgian.
Tielemans previously said he would "study my options in the summer and make a decision".
Arteta is looking to add more attacking reinforcements over the summer after missing out on Champions League football.
The Gunners have boosted their pursuit of Manchester City striker Gabriel Jesus, who is valued at around £50 million.
Arsenal's opening proposal for Jesus is around £30-35 million plus add-ons but the champions are holding firm for their asking price.