When you think of Bono or Lady Gaga, the term Silicon Valley entrepreneur hardly springs to mind.

For now, at least. The U2 frontman and pop sensation join Justin Timberlake and Ashton Kutcher among the growing ranks of celebrities who, rather than employ their star power to hawk consumer products, are increasingly driving high-tech investments.

Hollywood has always held a certain fascination for the monied elite, from Wall Street bankers to Middle Eastern oil sheiks. Now, it seems Hollywood is returning the favor and dabbling in a bit of capital resource-allocation of its own.

Timberlake made waves in late June when he bought a stake in ailing social network Myspace alongside digital advertising company Specific Media. The actor-singer will play a crucial role in revitalizing the web company.

We live in a world of brands, said Howard Bragman, a public relations executive and founder of the strategic media agency Fifteen Minutes. A handful of smart celebrities and their reps realize that all the areas where they can flex their marketing muscle are financial opportunities.

Savvy celebs are trying to fuse entertainment and social networking, closing the gap between performer and fan. That may well be the key to future success, according to Bragman.

Lady Gaga -- perhaps the most visible star on the social web -- teamed up with Google Executive Chairman Eric Schmidt's Tomorrow Ventures to invest in Backplane, slated to launch in the last week of August. Backplane -- a sort of social network for rabid fans of everything from football to, yes, pop music -- has raised over $1 million in funding.

Celebrities, above all others, have to understand the importance of new media in order to survive. Social media platforms, in particular, are where celebrity careers either thrive or decline, said Johanna Blakley, managing director at the University of Southern California's Norman Lear Center.

Timberlake's bet on Myspace is a risky one, but it signals an acknowledgment that buying into the entertainment business these days means buying into new media, not old media.

BEST AND WORST

Gaga has a double-digit percent slice of Backplane and a seat on the board, according to CEO and Founder Matthew Michelsen, who says he represents the pop diva in her Silicon Valley tech ventures.

The best way to understand Backplane is to look to football fans Michelsen calls facepainters -- the ones in the stands. The site goes beta in late August among Gaga's fans, whom she calls little monsters, according to Michelsen.

You don't know if those people are the president of a Fortune 500 company or the UPS man, Michelsen said. We want to provide a platform for them to interact around their love. It could be their favorite football team. It could be the little monsters. It could be Harley Davidson riders.

Timberlake has been active in start-ups like Apple iPhone gaming app developer Tapulous and Particle, which develops micro-video application Robo.tv, through the digital investment wing of his business empire, Tennman Digital.

With Myspace, however, the former 'N Sync member is not just putting his face on a product or bankrolling a venture. He gets an office, a staff of six, and a leadership role, according to Specific Media CEO Tim Vanderhook.

Timberlake isn't the only Hollywood royalty either making a serious push into technology.

Ashton Kutcher, who got his start in Dude, Where's My car?, has made a string of seemingly savvy investments from location-based social web Foursquare to Flipboard apps for the iPad. Most recently, his investment in Airbnb -- a website that matches travelers looking for a cheap room with homeowners looking to rent out -- won endorsement when venture capital firm Andreessen Horowitz led a $112 million round of financing for the fast-growing company.

But while some celebrities may be eager to develop their brand by demonstrating boardroom savvy, critics say a few investments may have been misplaced.

There arguably might be another tech bubble, said Christopher Smith, director of USC's Center on Communication Leadership and Policy. Once your shoe-shine person starts talking about stock deals, it's time to sell.

Irish rocker Bono of U2 fame is one of five co-founders of Elevation Partners, alongside former Apple CFO Fred Anderson and Silver Lake Partners co-founder Roger McNamee. He has an undisclosed amount of his own money invested in the fund.

But in 2010, Bono was dubbed the worst investor in America by blog 24/7 Wall St, and his firm's investments in Palm -- since taken over by Hewlett Packard -- Forbes Inc and Move.com have been roundly panned.

Not every association works, but in the best cases they raise the profiles of the projects they are involved with, entice other investors and inspire consumers, Bragman said.

The key is authenticity. They have to choose associations that are credible and organic if they wish to succeed.

(Editing by Edwin Chan and Lisa Shumaker)