"Together again... Gee, it's good to be together again. #SNL40."

So read a tweet from the official N'Sync Twitter account on Saturday. That means both the Backstreet Boys and N'Sync will be performing at the star-studded anniversary show tonight.

Of course this is hardly shocking as Justin Timberlake has been involved in some of the most memorable guest star spots on the show in recent years. "Dick in a box," anyone?!

So who else will be watching tonight?

SNL 40 airs at 8 p.m. Sunday night on NBC.