The last time all five members of the band were together was for their performance at the 2013 MTV Video Music Awards.
Carey and Cannon's twins, Monroe and Moroccan, celebrated their birthday with a bouncy house and balloons.
The trip to Italy occurred just five days after Perry confirmed her relationship status to ET.
Here's a look at when ET first met *NSYNC.
Justin Timberlake, JC Chasez, Lance Bass, Joey Fatone and Chris Kirkpatrick reunited in Hollywood to receive a star on the Hollywood Walk of Fame on April 30.
The boy band got back together to celebrate getting their star on the Hollywood Walk of Fame on Monday.
The pop diva is returning to The Colosseum at Caesars Palace beginning on July 5.
The group's loyal followers camped out overnight to get the best spot at the boy band's Hollywood Walk of Fame induction.
The singer enjoyed a pool day with her tour crew as they prepare to head off on the 'Reputation' tour.
La Toya also says Blanket Jackson is enjoying 'being a kid,' revealing to ET the family often has game nights! The season three finale of 'Hollywood Medium with Tyler Henry' airs May 2 at 9 p.m. ET/PT on E!.
The famed Swedish pop group broke up in 1982.
The 'Cry Pretty' singer is growing more and more confident by the day after her scary fall last November.
After the 'Saint Pablo' rapper released the baffling, trolling song 'Lift Yourself' to his website, L.A.'s Power 106 radio station aired what appears to be the rapper grappling with the controversy he's caused on Twitter.
The grand opening for Manilow's Vegas show is set for his birthday weekend, June 14-16, 2018.
