The trendy descend as British fashion royalty lands at the Grove

Star sightings are common at the Grove, but on Thursday the breathless anticipation was for the grand opening of fashion retailer Topshop and its men’s brand, Topman.

The long-awaited debut marked the British brands’ first West Coast store and brought out hordes of shoppers, some of whom stood in line for hours.

“I’m pumped. We’ve been waiting for so long and now it’s finally getting close,” said Sydney Nassiri, 17, who arrived at the Grove at 9 a.m. with her friend Laurel Bylin.

It was a retail mob scene at the shopping center in L.A.’s Fairfax district as people angled to be among the first to snatch up crochet and lace camis, bold floral high-low dresses and color-block tops.

Shoppers stood in a two-pronged line that flanked the main path of the shopping center; the earliest arrived at 5 a.m. At its height, Grove officials estimated, the crowd numbered 10,000, making it the center’s biggest store opening ever.

Adding to the circus atmosphere was the faux British street fair staged as the line to get into the store grew. Executives from Topshop and Topman chatted with Grove owner Rick Caruso, while pop singer Demi Lovato performed before the doors opened shortly after 4 p.m.

The opening followed a Wednesday night launch party in West Hollywood that brought out Kim Kardashian, Jennifer Lopez, Chris Brown, Paris Hilton and two of the Jonas Brothers.

Despite the thousands in line, only a few dozen were allowed in at a time. Among them was 19-year-old Karina Aldana, who made a beeline for the accessories section.

“I shop a lot, and this is pretty high up on my list,” the Glendale nursing student said. “I’ve gone to Chicago for Topshop and I thought I knew what to expect, but this is even better.”

Topshop started in Britain in 1964 and now has hundreds of stores in 37 countries. Its Oxford Circus flagship is among the largest fashion stores in the world.

The brand, which sells clothes, shoes, makeup and accessories, is known as a trendsetter. It was an early proponent of partnering with celebrities, such as supermodel Kate Moss, to create exclusive collections. Its fashion show this weekend in London will feature an industry novelty: full access for the public via an app, streamed video and Google+ Hangouts.

Video: The scene at the Grove

Topman was opened as a separate chain for men in 1978, but the stores often cohabitate with Topshop locations. Both are subsidiaries of Arcadia Group, Britain’s largest private clothing retailer, which is run by Sir Philip Green.

Topshop and Topman entered the U.S. market four years ago in New York and have since expanded to Chicago, Las Vegas and more than a dozen boutiques in Nordstrom stores.

In New York, the chain’s revenue and profit are up by double digits from a year ago, said Topman Managing Director David Shepherd. But there was a need to bring the brands to California shoppers, who make up about 25% of Topshop and Topman’s online traffic, he said.

Several Southern California locations were considered, including the Third Street Promenade, Beverly Hills, Glendale Galleria and the Americana at Brand in Glendale, but the Grove “was absolute top of the short list,” said Robert Cohen, a real estate broker who represented Topshop and Topman.

The two-story, 30,000-square-foot store, which previously housed a Banana Republic, features clothing matched to Southern California’s warmer weather. Its wooden panels and flooring distinguish the decor from the cooler tile and chrome in the other U.S. stores.

Caruso, founder and chief executive of Caruso Affiliated, said he had been in talks with Green for about two years and had campaigned hard for a Topshop location. The brands now expect the Grove store to be the second-most profitable U.S. outpost, after New York.

“It’s a coup for us,” Caruso said. The Grove last year recorded a huge $1,900 per square foot in retail sales, and with the addition of Topshop and Topman, “we’re just going to exceed that in the coming year.”

The Grove and neighboring Farmers Market are home to several major apparel retailers, including Forever 21 and Zara, which, like Topshop, focus on fashion-forward young adults. Topshop will also vie against H&M;, American Apparel, Foreign Exchange and Angl, but a tight market doesn’t seem to be a concern.

“Los Angeles is obviously a fashion capital,” Shepherd said. “But when looking at the competition here, we have the same situation in New York and Chicago and we’re performing well in those areas.”

Not everyone showed up Thursday just for the retail opportunities.

Makaela Glancy, 13, arrived at the Grove at 6 a.m. from San Diego. Although she was excited to shop for Topshop clothes and accessories, she came mainly to see Demi Lovato and passed out homemade paper hearts to other shoppers in line.

“She’s already cried once today because Demi did a sound check and waved at her,” her mom, Bobbi Kohler, said.

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Times staff writer Frank Shyong contributed to this report.