Norway under-21s stopper Klaesson has become United's latest recruit, joining the Whites for an undisclosed fee from Norwegian side Valerenga.
The 20-year-old has signed a four-year deal and replaces Kiko Casilla who has left for La Liga side Elche on a season-long loan.
Coronavirus rules and regulations meant that Klaesson was initially required to quarantine upon his arrival from Norway before undergoing a Whites medical.
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But the young 'keeper was finally unveiled on Saturday morning and is excited to join a club who stormed to a ninth-placed finish upon last season's Premier League return.
"It's been a tough couple of days with some quarantine and stuff like that but I am really happy to finally be here," Klaesson told LUTV.
"It's a really big club with a lot of history so I'm really happy to be here.
"It's a club with a lot of history with a lot of potential after being promoted to the Premier League."
The fee for Klaesson is believed to be in excess of £1m and the Norwegian becomes a second new face for United's first-team squad.
United's main new signing of the summer so far has been left back Junior Firpo who joined from Barcelona for €15m.
First team winger and former Whites loanee Jack Harrison also joined on a permanent deal from Manchester City for £11m whilst youngsters Lewis Bate, Sean McGurk and Amari Miller have also been signed, initially to link up with the under-23s.
Leeds hope to add a centre midfielder and a winger to their first team squad before the transfer window shuts at 11pm on Tuesday, August 31.
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Thank you Laura Collins