U2 rocker Bono, actress Olivia Wilde and tycoon Richard Branson have become the latest stars to sign up for Matt Damon's bizarre bathroom strike in aid of a water charity.

The Bourne Identity star launched his odd campaign earlier this year (13), pledging not to use a restroom until everyone in the world has access to clean water.

Celebrities including Jessica Biel and Jason Bateman threw their weight behind the drive in aid of Water.org by filming their own public service announcements to publicise the campaign.

Now Bono, Wilde and Branson have joined in the fun and brought attention to the global sanitation crisis.

In a joint message, the trio states, "We won't go to the bathroom until everyone in the world has access to clean water and sanitation."

Bono then jokes, "I remember when Matt first brought up the idea, it was at a meeting of the Illuminati," and Wilde adds, "Bono was so mad. Oi! Damon! Who let you into our secret Illuminati meeting?"