The group set a record in 2000 when their LP 'No Strings Attached' sold 2.416 million copies in just seven days, but three days after the British singer released new album '25' on Friday (20.11.15), it had already clocked over 2.433 million sales in downloads and physical copies in the US.
And the 'Bye Bye Bye' hitmakers have now praised the 'Hello' singer for her achievement.
Lance Bass wrote on Twitter: ''We officially say Bye Bye Bye as @Adele says Hello to the World Record of Most Albums Sold In a Single Week. Congratulations!! #IDemandARecount #NSYNC #Adele (sic)''
Bandmate Joey Fatone is also pleased it is Adele who has broken their record.
He told Billboard magazine: ''In all honesty, Adele is the truth -- kinda excited a rare talent like hers is in the same breath as our group. I'm a huge fan. I even bought the damn album.''
However, Joey admits he was amazed anyone had managed to smash their first-week sales.
He said: ''Records are always meant to be broken, but with technology and current music business model, I thought this one would be tough to beat.''
While Justin Timberlake has yet to comment, J.C. Chasez simply posted: ''Well done Adele.'' and Chris Kirkpatrick retweeted a post about the record being broken, but didn't add any remarks of his own.