U2 frontman Bono finally has found what he's looking for--at least when it comes to tech investments.

The rock star is a cofounder of the investment fund Elevation Partners, which owns 1.5 percent of Facebook, a stake that could be worth $1.5 billion following the social network's upcoming initial public offering. That's a considerable reversal of fortune for someone once called "the worst investor" in America, thanks some highly embarrassing misfires.

Founded in 2004 by Bono and a host of Silicon Valley bigwigs--including Silverlake Partners founder Roger McNamee, Apple board member Fred Anderson, and Electronic Arts CEO John Riccitello--Elevation's stated mission was "to help media and entertainment businesses develop and market great content." In 2006, the fund made its first big investment: $300 million in Forbes Magazine. The property's value dropped 80 percent over the next 12 months.

In 2007, Elevation invested a reported $460 million for 25 percent of the device manufacturer Palm. Shortly after, Palm was acquired by HP for $1.2 billion, leaving Elevation with a measly 1.5 percent return. Elevation also invested $100 million into the online review site Yelp, which has since been plagued with class-action lawsuits and extortion accusations.

In 2010, Elevation Partners made the first of three investments in Facebook. By 2011, the firm invested a total of $270 million into the social media giant, and, was sitting pretty in anticipation of the company's public offering. Apart from Elevation, Bono participated in a $250 million second-round investment in the document sharing start-up Dropbox.

Bono was introduced to the Silicon Valley elite by Facebook COO Sheryl Sandburg. Before joining the social network, Sandburg worked at the U.S. Treasury Department, where she successfully enticed Bono to assist in the agency's aid initiatives in Africa. Bono is just one of many celebrities taking a turn in the tech investment world over the past few years. Lady Gaga and Kanye West both backed turntable.fm, Leonardo DiCaprio is a funder of social media platform mobli, and Ashton Kutcher has thrown money towards Foursquare, Flipboard, Milk, and Airbnb among others.

Regardless of where Bono and Elevation Partners go from here, one thing is for certain: the star's involvement in Facebook will make him the richest rock star in the world, dwarfing the current title owner: Sir Paul McCartney.