Boy band 'N Sync secretly reunited earlier this month (Oct11) to help Chris Kirkpatrick celebrate his 40th birthday.
The singer threw a big party at his Orlando, Florida home and invited friends and family to help him mark the age milestone.
'N Sync stars JC Chasez, Joey Fatone and Lance Bass were all in attendance, and the event turned into an unofficial reunion for the Bye Bye Bye hitmakers when Justin Timberlake turned up unexpectedly.
The get together was the first time in six years all five members of the boy band were in the same room.
A source tells Us Weekly magazine, "Chris was surprised."