Kylian Mbappe signed a five-year deal to move to Real Madrid from Paris Saint-Germain on Monday and called the move a "dream come true".
"The Whites have strengthened their squad with a world superstar," Real said on their website.
"Real Madrid have reached an agreement for the player to be at Real Madrid for the next five seasons," they added.
The announcement is the culmination of Real's long courtship of one of the most prolific forwards in world football.
"So happy and proud to join the club of my dream @realmadrid. Nobody can understand how excited I am right now. Can't wait to see you, Madridistas, and thanks for your unbelievable support," 25-year-old Mbappe added on social media.
Real first courted Mbappe in 2012 when they invited the 13-year-old to spend a week with them. During the visit he was photographed with his idol Cristiano Ronaldo.
On Monday, Ronaldo, now playing in Saudi Arabia, commented on Mbappe's Instagram post, showing the teenager in a Real sweatshirt pointing at the club badge.
"My turn" to have my eyes on you, wrote Ronaldo. "Excited to see you light up the Bernabeu."
Mbappe had agreed to move to Real in February and announced in May he would leave PSG at the end of the season.
Real, fresh from winning their 15th Champions League on Saturday with a 2-0 victory over Borussia Dortmund, moved to confirm the deal on Monday before Mbappe is involved in pre-Euro 2024 friendlies for France.
"Welcome to the best club in the world," former Real goalkeeper Iker Casillas posted on X.
"It's never too late if the feeling is good. With you begins the road to the 16th..."
It was a sentiment echoed by defender Eder Militao, who came on at the end of the victory over Dortmund. "Welcome KMbappe, for the 16th..." wrote the Brazilian on X.
Mbappe will earn 35 million euros ($38 million) a season, according to reports in Spain.
Mbappe's last contract with PSG, signed in 2022, was a two-year deal worth some 72 million euros before tax with loyalty bonuses of a similar amount and a signing-on fee of 150 million euros.
His signing was popular with the club's goalkeepers.
"Welcome to your new home," Belgian Thibaut Courtois posted on X,
"Welcome crack!" said Ukrainian Andriy Lunin on Instagram.
Midfielder Eduardo Camavinga simply posted a picture of himself and Mbappe side by side playing for France.
A World Cup winner as a teenager in 2018, Mbappe scored a club record 256 goals for PSG since joining the Qatar-owned club from Monaco on an initial loan in 2017.
He eventually moved to PSG in a 180-million-euro deal -- all at the age of 18.
Mbappe helped PSG to six Ligue 1 titles and steered them to the 2020 Champions League final, but they lost to Bayern Munich.
He scored a hat-trick in the World Cup final against Argentina in Qatar in 2022 but still finished on the losing side as Lionel Messi's Argentina won on penalties.
PSG lavished huge sums to put Mbappe, Brazil star Neymar and Messi in the same team, hoping to finally unlock the Champions League puzzle. But the French club came up short.
As Mbappe's fame has grown, so has his importance to both the French national team and France the country.
President Emmanuel Macron intervened to persuade him to stay at PSG in June 2022 when a move to Real seemed almost cut and dried.
At Real, who also won back the La Liga title from fierce rivals Barcelona this season, Mbappe will form a formidable attacking trio with Brazilian forward Vinicius Junior and England international Jude Bellingham.
A lethal trio of such unequivocal quality brings to mind Real's glittering era with Ronaldo the star in a trio that also included Gareth Bale and Karim Benzema.
Mbappe now has the chance to emulate his idol, Madrid's all-time top goalscorer.
At PSG, Mbappe was briefly the junior member of a stellar trio with Messi and Neymar. At Real, Mbappe will be the senior striker.
Real started 23-year-old Rodrygo Goes alongside 20-year-old Bellingham and 23-year Vinicius in Saturday's Champions League final.
In February, coach Carlo Ancelotti was asked how he would accommodate Mbappe.
"Good players need to know how to play together. The important thing is to maintain a balance," he said. "For me, the most important things in a team are: quality and balance. If you can combine these two things, you'll be successful."
As part of a formidable rebuild, the club has already brought in young midfielders to take over from retiring Toni Kroos and 39-year-old Luka Modric in Camavinga, Federico Valverde and Aurelien Tchouameni, all 25 or under.
They have also signed teenage Brazilian star Endrick.