Who is that in the front row at New York Fashion Week? A movie star? A teen heartthrob? A Real Housewife?

Try all of the above.

Fashion's historically closed circle has expanded its definition of 'notables,' the people considered worthy of a front-row seat at a fashion show. Spots once reserved for top magazine editors, luxury department-store buyers and the occasional A-list celebrity have been infiltrated by publicity-seeking TV actresses, reality show personalities and over-the-top bloggers.

'It's incredibly more complicated. We may as well be seating shows on Mars right now because there's so much to think about,' says Alison Brod, founder of Alison Brod Public Relations, who has been working with fashion week for 15 years.

Designer Cynthia Rowley hosted Abigail Breslin, the Oscar-nominated actress, in the front row of her show last season, where she was photographed with Beth Riesgraf of the TNT drama 'Leverage,' Angela Simmons of the former MTV realityseries 'Run's House' and Megan Hilty of the NBC musical show 'Smash.' An unlikely quartet lined the front row at Dennis Basso's show: comedian Joan Rivers, soap star Susan Lucci, Donald Trump's daughter Ivanka and former MTV reality star Kristin Cavallari.

In this new game, with its ever-growing list of players, there are no hard and fast rules about who gets a prime space and who is turned away. 'One man's garbage is another man's treasure . . . a front row at one show might be a declined at another show,' says Kelly Cutrone, founder of the branding firm People's Revolution and a personality in her own right, known, among other things, for her judging stint on 'America's Next Top Model.'

Ms. Cutrone helped put together an unusual trio at Jeremy Scott's show last season: Joe Jonas, of Disney Channel and Jonas Brothers fame, sat alongside edgy DJ Leigh Lezark and Terry Richardson, a fashion photographer known for risque images. 'That three-shot says it all,' Ms. Cutrone says of the resulting photograph.

Make no mistake, experts say, the front row matters. Before the first look comes down the catwalk, many attendees judge a show based on who can be seen attending, says Hampton Carney, a partner at Paul Wilmot Communications, which is handling seating for shows such as Reem Acra and Christian Siriano. He equates the job with seating 'a really great wedding or a fabulous dinner party.'

Designers typically hire PR firms to help with their fashion shows and handle seating assignments; the designer's team makes revisions and provides the final sign-off. Among the dozens of invitation-only shows at New York Fashion Week, the average front row will have about 125 assigned seats, says Lynn Tesoro, co-founder and partner at HL Group.

Some designers lengthen their runways or reconfigure to include more front-row seats. The Marchesa show, for which HL Group is handling seating, has 224 this season. Even that doesn't satisfy everyone: Some sections of an extended front row are considered better than others, in part because they offer a better view of the clothes.

PR firms also handle invitation requests. Once reserved for the media, contacts are now shared widely online, and requests are exploding in number. 'There's a huge onslaught,' Ms. Tesoro says.