It's not gossip: online entertainment site TMZ has gone mobile.

The ad-supported, standalone mobile site will carry content news and video content from TMZ.com. Sony Pictures Home Entertainment's "Walk Hard" is the presenting sponsor. TMZ will soon follow this mobile effort with an on-deck site on AT&T Wireless.

"This is really one of the biggest launches of an on- and off-deck entertainment mobile site in the U.S.," said Lars Albright, vice president of business development at Waltham, MA-based Quattro Wireless, which built and powers the site.

Targeting TMZ's core 18-34 demographic, the mobile site will run breaking celebrity news, real-time headlines and developing stories for free.

In addition, consumers can browse news headlines and updated photo galleries, watch videos, participate in mobile surveys and get advance previews of stories that will air daily in the TMZ television program.

Consumers will be able to sign up for breaking news alerts powered by Quattro and delivered through text message.

The mobile site is visited by typing TMZ.com in the Web browser of a mobile phone. Users can also text to 52662 to have a link sent to their phone.

TMZ will promote the mobile site on its regular Web site at www.tmz.com and other partner sites. The brand will also debut a site-wide send-to-mobile widget.

TMZ claims to be the most trafficked entertainment news site online nationwide, with nearly 11 million unique visitors each month as reported by comScore Media Metrix.

The celebrity news brand is a joint venture of Warner Bros. Television Group's Telepictures Productions and AOL. All three companies are part of the Time Warner Inc. family.

Using Time Warner assets will be part of TMZ's market strategy.

For example, AOL's Third Screen Media mobile ad network will sell ad inventory on the mobile site in a 50:50 split with Quattro.

Meanwhile, as part of its charter sponsorship of the mobile TMZ, Sony Pictures Home Entertainment will promote the April 8 debut of a two-disc unrated DVD and Blu-ray High Def for "Walk Hard: The Dewey Cox Story," a comedy produced by Judd Apatow and starring John C. Reilly.

The TMZ mobile site will run an exclusive clip from the movie's DVD.

Mr. Albright said the site was designed keeping in mind the advertiser experience as well.

"It's extremely friendly to advertisers," Mr. Albright said. "The site was designed with advertising in mind.

"We're offering both CPM and CPC opportunities on the site and opportunities for the ads to be effectively integrated into the page design to encourage the highest possible click-throughs," he said.