Codenamed Operation Anti-Security, the statement was originally released on the Pastbin website and has since been tweeted on LulzSec and Anonymous' Twitter pages.
The note stated that LulzSec was going to join with Anonymous, targeting any and all government websites or systems it encountered:
"Welcome to Operation Anti-Security (#AntiSec) - we encourage any vessel, large or small, to open fire on any government or agency that crosses their path. We fully endorse the flaunting of the word "AntiSec" on any government website defacement or physical graffiti art.
"We encourage you to spread the word of AntiSec far and wide, for it will be remembered. To increase efforts, we are now teaming up with the Anonymous collective and all affiliated battleships."
The post went on to reiterate Anonymous previous sentiment that the attacks are a form of protest against certain governments internet censorship and moderation policies:
"As we're aware, the government and whitehat security terrorists across the world continue to dominate and control our Internet ocean. Sitting pretty on cargo bays full of corrupt booty, they think it's acceptable to condition and enslave all vessels in sight.
"Our Lulz Lizard battle fleet is now declaring immediate and unremitting war on the freedom-snatching moderators of 2011."
The news that Anonymous and LulzSec are in fact working together comes after a rift between the two groups was speculated. An argument that took place over 4Chan's message boards indicated that Anonymous contributors had conducted attacks on LulzSec after the group released the personal information 62,000 random internet users.
LulzSec went on to call for any interested party to join it and Anonymous, "Whether you're sailing with us or against us, whether you hold past grudges or a burning desire to sink our lone ship, we invite you to join the rebellion.
"Together we can defend ourselves so that our privacy is not overrun by profiteering gluttons. Your hat can be white, gray or black, your skin and race are not important. If you're aware of the corruption, expose it now, in the name of Anti-Security."
LulzSec's campaign announcement comes just as the U.S. has reported its plans to increase the maximum sentences its courts can give hackers. The new laws -- which are yet to pass -- would mean that any hacker caught accessing government files could potentially face 20 years in prison.
LulzSec has already claimed responsibility for two recent attacks on the U.S. Senate and CIA's websites.
The campaign was revealed just as the group affirmed in a separate statement celebrating its thousandth tweet argued that it is not a hacktivist group. The alternative mission statement outlined a much more anarchistic leaning, arguing that LulzSec has and will only ever carry out attacks that it finds amusing.
The statement did not reveal which country, department or agency LulzSec intends to target next.