Arsenal have signed Gabon striker Pierre-Emerick Aubameyang from Borussia Dortmund for a club record £56m.
The Gunners had two bids for Aubameyang rejected by Dortmund before agreeing a fee that eclipses the £46.5m they paid for Alexandre Lacazette in July.
Arsenal said the 28-year-old – the 2015 African Footballer of the Year – had joined on “a long-term contract”.
Dortmund agreed to the sale after striking a deal to sign Chelsea forward Michy Batshuayi on loan.
Aubameyang said: “I’m really happy to be here in this great team.
“The club has such a big history and great players like Thierry Henry. He’s an example for us strikers. I’m a fast player and I score goals too, like Henry a little bit. I think I have to work a lot to be like him, but I will do.
“I hope that we will come back to the top as soon as possible. I will do my best to join in.”
Aubameyang scored 141 goals in 213 games for Dortmund, including 21 in 24 matches this season.
After his move to Arsenal was confirmed, Aubameyang called himself “a crazy kid” in a message to Dortmund fans posted on Instagram, also apologising for the manner of his departure.
Aubameyang – who will wear the number 14 shirt at Arsenal – joined Dortmund from French club Saint-Etienne in 2013.
Elsewhere,Tottenham have signed Paris St-Germain winger Lucas Moura for £23m.
The 25-year-old Brazilian, who has signed a contract until 2023, joined PSG for £33.5m from Sao Paulo in 2013 but has made just six substitute appearances this season.
“It’s a new chapter of my life, a new challenge,” he said.
“I will give my best for this club because I think we have a lot of quality and we can win big things. Why not the Champions League?”
“I’m so happy. It’s a big club and I need to enjoy it, work hard and show my quality.”
Lucas – who will wear the number 27 shirt for Spurs – scored 46 goals and contributed 50 assists in 229 appearances for the French club.
Finally, Chelsea have signed Arsenal striker Olivier Giroud on an 18-month deal for about £18m.
France international Giroud, 31, leaves Arsenal having scored 105 goals in 253 games since signing from Montpellier for a reported £12m in June 2012.
“Chelsea is one of the biggest teams in the Premier League – they have won maybe the most trophies in the last six or seven years,” Giroud said in a statement.
“It’s a massive club and I am proud to sign for Chelsea, and I’m looking forward to playing.”
Giroud’s final appearance for Arsenal was as a substitute in Tuesday’s 3-1 defeat by Swansea.
After his move to Chelsea was confirmed, Giroud thanked Gunners fans for their part in a “beautiful story” after “five and a half amazing years within the Arsenal family”.
Arsenal manager Arsene Wenger paid tribute to Giroud’s “great service” to the club.