Manchester United have completed the signings of defenders Matthijs de Ligt and Noussair Mazraoui from Bayern Munich.
De Ligt's move is worth €50m (£42.7m), with an initial €45m (£38.4m) plus €5m (£4.3m) in add-ons, with the player available for United's opening Premier League match against Fulham on Friday, live on Sky Sports, having been registered by midday on Thursday.
The 24-year-old Netherlands international centre-back has spent two seasons at Bayern since signing from Juventus, playing 73 times and scoring five goals.
- Matthijs de Ligt thrived under Erik ten Hag - Could he do so again at Man Utd?
- Transfer Centre LIVE! | Paper Talk
- Get Sky Sports | Stream Sky Sports on NOW
De Ligt also played under Man Utd boss Erik ten Hag at Ajax, where they won the Eredivisie in 2019.
The defender, who has also won league titles with Juventus and Bayern, said: "As soon as I heard that Manchester United wanted me, I felt an excitement about the opportunity of a new challenge at such an historic club.
"In the conversations that followed, I was impressed by the vision that the football leadership set out, and the role they saw for me in it.
"Erik ten Hag shaped the early stages of my career so he knows how to get the best out of me and I cannot wait to work with him again.
"I know what it takes to succeed at the highest level, and I'm determined to continue that record at this special club."
De Ligt strengthens United's central defence following the departure of Raphael Varane, with fellow summer arrival Leny Yoro set to miss up to three months with a foot injury sustained against Arsenal in pre-season.
Full-back Mazraoui, 26, joins for a €15m fee (£12.8m) with a possible €5m (£4.2m) in add-ons.
Mazraoui also played under Ten Hag at Ajax. He won three league titles with the Dutch club and another with Bayern.
The Morocco international has made 28 appearances for his country and reached the semi-final of the 2022 World Cup with them.
He has signed a four-year deal with the option of a further year and arrives on the day that full-back Aaron Wan-Bissaka's departure to West Ham was confirmed.
Mazraoui: Incredible feeling to join Utd
Mazraoui said: "It's an incredible feeling to be a Manchester United player, and I cannot wait to walk out at Old Trafford wearing the red shirt.
"I know that I'm joining the club at an exciting time; everyone I've spoken to has the same ambition for us to win trophies together and I can feel the determination to achieve that."
Manchester United sporting director Dan Ashworth said: "Noussair is a dynamic, attacking full-back who can play on both the right and left side of defence. His experience and versatility will make him an excellent addition to our squad.
"Having already won a number of trophies in his career, we know that Noussair's winning mentality will be a real asset to the group as we work together to deliver the success required of Manchester United."
Why Man Utd moved for De Ligt and Mazraoui
The deal which sees De Ligt head to Old Trafford is worth €45m (£38.5m) with a potential further €5m (£4.2m) in add-ons.
United view it as an attractive fee for a young but extremely experienced and high-quality centre-back, who has enjoyed success everywhere he has played.
Mazraoui is viewed at the club as a young, versatile and dynamic full-back - strong defensively and going forward on the left or right.
The simultaneous arrival of De Ligt makes it four major signings for United completed before the start of the season, significantly strengthening the squad and addressing priority positions.
United's focus to turn to midfield recruitment
United are expected to focus on midfield recruitment following the arrivals of Mazraoui and De Ligt.
However, any potential incomings will be dependent on budget and valuation.
Dialogue remains open with Paris Saint-Germain over Manuel Ugarte but, as yet, the French club are not budging on price.
United are being patient with a little over two weeks of the window to go in the knowledge that PSG may need to sell and with the player very keen on a move to Old Trafford.
Personal terms are therefore not expected to be a problem.
United are looking at other midfielders as well, though, and talks continue with Burnley over Sander Berge, who missed Monday's win over Luton with an injury.
Monaco's Youssouf Fofana and Fiorentina's Sofyan Amrabat also remain options as well.
With budgets, it may require a sale for United for them to go back into the market. There have been no further bids as yet for Scott McTominay and Casemiro is now expected to stay.
How will Man Utd's new-look defence line up?
Sky Sports' Melissa Reddy:
Manchester United had two main aims for reinforcing their defence this summer; to enhance the steel of it, especially in duels, and to change the dynamic.
The coup of ousting Real Madrid to land Leny Yoro added extra athleticism, aerial threat, and a technical, ball-winner tipped to develop into one of the premier centre-backs in the game.
The teenager suffering a fractured metatarsal in the opening pre-season game of the US tour was hugely unfortunate, but United have signed him for the long term not just the first few months of the season.
Even before that setback, the club intended to add at least one more option in the heart of defence, which was ravaged by injuries last time out, but also lacked balance and progressive attributes.
Matthijs de Ligt had been proposed to Erik ten Hag - who wanted him in his first summer at Old Trafford - by United's recalibrated recruitment team as a target to raise their physical and technical ceiling; the man to dominate defensive duels.
The composed stopper is viewed as a good foil for the aggressive, instinctive Lisandro Martinez; balance on the right and left but also in approach.
At 25, De Ligt's scale of experience in different environments of high expectation, natural leadership, and his ability to implement Ten Hag's style of play made him appealing.
There is a feeling his strengths weren't maximised at Bayern Munich, who have been in flux, and that his profile plus attitude will be a boost to United.
Perhaps the most instructive move to showcase the change of dynamic is switching out Aaron Wan-Bissaka - a one-v-one defensive specialist - for the highly technical, two-footed Noussair Mazraoui. Also recruited from Bayern, he can cover both full-back positions, is press-resistant and better suited to building play.
Mazraoui - effectively paid for by Wan-Bissaka's exit to West Ham - was one of the key cogs of Ten Hag's successful Ajax side, where he helped bring out the best of Antony's game.
There will be natural cynicism that this continues United's policy of buying who the manager is familiar with rather than building towards a club identity.
The counter will be that by adding progressive players that offer a varied dynamic, United are actually recruiting for the game model they are committed to.
The difference is that Ten Hag is not driving recruitment as was the case before the new football leadership team was in situ. Targets have been proposed to him based on their suitability to the style of play, their availability on the market, and the opportunity to actually get a deal over the line - financially and logistically.
Victor Lindelof could still leave before the window closes and the addition of a left-sided defender remains open.
United have been more proactive and methodical in their recruitment this summer, but there is still work to do beyond the rearguard - especially in midfield.
How are Man Utd going to line up against Fulham?
Flex, speaking on Good Morning Transfers on Sky Sports News:
"Ten Hag has got some difficult calls to make. Man Utd need a period of calm. They need to get some injured players back into the starting XI.
"Andre Onana will certainly be in goal this season but how the defence will look could be interesting.
"We know about Luke Shaw's injury problems. Could that mean a slight change of role for Lisandro Martinez? He started at left-back in the Community Shield against Man City and could start the season there for United, leaving new boy De Ligt to partner Harry Maguire at the heart of the defence.
"Diogo Dalot was one of United's better players last season and he now faces competition from Mazraoui for the right-back position. But we could also see Dalot on the left with Mazraoui on the right, allowing Martinez to play in his more familiar centre-back role.
"Kobbie Mainoo and Casemiro look set to continue in the middle of the park against Fulham and it could be a big season Mason Mount. He'll be hoping to leave his injury problems behind him this season and have a big impact for United.
"An injury to Rasmus Hojlund has hampered Ten Hag's plans somewhat in attack. Bruno Fernandes filled the false nine position against City and will continue their in the absence of Hojlund and while Joshua Zirkzee continues to settle in at Old Trafford. He'll be joined in attack by two of Marcus Rashford, Amad Diallo and Alejandro Garnacho on the flanks."