"It is no secret I have been a fan of this great club since I was a small boy," Hojlund said.

"I dreamed of walking out at Old Trafford as a Manchester United player."

He is United manager Erik ten Hag's third summer signing after Mason Mount joined from Chelsea for £55m and Inter Milan goalkeeper Andre Onana arrived for £47.2m.

Ligue 1 champions Paris St-Germain were also reportedly interested in Hojlund as a potential replacement for France captain Kylian Mbappe, whose immediate future is unclear.

Hojlund will miss the opening weeks of the 2023-24 season, which United begin against Wolves on Monday, 14 August, after picking up a small injury during pre-season training with Atalanta.

"I am incredibly excited by this opportunity to turn a dream into a reality, and I am determined to repay the faith the club has shown in me," Hojlund added.

"It is still early in my career, but I know I am ready to make this step up and play with this group of world-class players.

"Once I had spoken to the manager, I knew this environment would be perfect for my development; I am relishing the opportunity to work with one of the best coaches in the world.

"Under his guidance and support I know that I am capable of achieving great things together with my new team-mates at this special club."

Hojlund began his senior career at Copenhagen, making his Danish Superliga debut aged 17 in 2020 before switching to Austrian side Sturm Graz two years later.

He spent only six months in the Austrian Bundesliga after joining Sturm in January 2022 but scored a goal every other game, finding the net nine times in 17 starts.

That impressive form led to his move to Atalanta for a reported £15m, 10 times what Sturm Graz had paid for him.

He made his international debut in 2022 and has scored six goals in six games in qualifying for Euro 2024.

"Rasmus is a truly exceptional talent; he possesses technical and physical attributes which rank him among the best players in the world for his age group," said Manchester United football director John Murtough.

"Throughout the summer we have acted quickly and decisively to secure our primary targets. This will ensure Erik and his coaches have the best opportunity to prepare the squad to push for further success."

Analysis

BBC Football reporter Simon Stone, Old Trafford

Hojlund received a rapturous reception as he made his way out of the players' tunnel to the centre circle, where he held up a shirt bearing his name - but no number - before Manchester United's friendly with Lens.

His presence has generated a huge amount of attention, with a Danish TV crew flying in solely to cover the moment.

The transfer represents something of a gamble for United, who were heavily linked with a move for Harry Kane.

In the recent past, they have gone for experienced forwards in the form of Radamel Falcao, Zlatan Ibrahimovic and, most recently, Cristiano Ronaldo.

Hojlund is at the other end of the age and development stage. It will be fascinating to see whether manager Erik ten Hag can develop him the same way he brought through so many excellent Ajax players that he guided to the semi-final of the Champions League in 2019.

One game a week for the first four weeks of the Premier League season allows time for Hojlund, once fit, to settle in. It promises to be a fascinating period for this self-confessed United fan, whose reputation has grown considerably since he cost Sturm Graz £1.3m 18 months ago.