"I love it ... Hong Kong will become my Asian base," said the 24-year-old, spiky haired piano prodigy, who was born in Shenyang in northern China, but who recently became a Hong Kong resident through an elite, fast-track migrant admission scheme.

Lang's commitment to China's most international city, comes nearly 10 years after British dignitaries -- including the last governor Chris Patten -- returned Hong Kong to Chinese rule on July 1, 1997, on a rainy night steeped in ceremony and emotion.

Since then, well over half a million Chinese such as Lang have spilled across the border to live in Hong Kong -- pushing the city's population up to almost seven million.

Nowadays, tight immigration controls are in place -- with immigration capped at 150 individuals per day, mainly for the Chinese wives and children of Hong Kong residents.

But with one of the world's lowest birth rates, these immigrants now account for around 80 percent of Hong Kong's annual population growth, making them an increasingly vital part of Hong Kong society by helping replenish its ageing workforce.

"Hong Kong is 100 percent a part of China. It's very international and liberal, with an amalgam of cultures. A bit like America, but with a lot more Chinese culture," said Lang.

Cross-border marriages have proliferated -- with 4 out of every 10 marriages registered in Hong Kong now involving a Chinese mainlander.

"Most are what people would regard as low-skilled immigrants, the family of Hong Kong members, and many of them are women," said Leung Hon-chu, a sociologist at Baptist University.

STRUGGLE

But unlike Lang Lang, social scientists say most immigrants face a life of hardship, and are often stereotyped as poorly educated opportunists chasing jobs and social welfare.

"When I go out to the markets to buy clothes and food, I experience prejudice," said 39 year-old Ng Chi-lin, a mainlander who like many others had to wait several years to join her family in Hong Kong.

"Sometimes, if I don't buy something after asking the price, the stall-holders say I'm a bloody mainland woman who's too poor to buy anything," she added.

"Many are quite disappointed after coming to Hong Kong. There's an expectation gap," said Chua Hoi-wai, a director of a large social welfare group.

In 1999, the hopes of many aspiring cross-border families were dashed, when the Hong Kong government successfully asked China's parliament to overturn a legal ruling by Hong Kong's highest court that granted residency to all mainland children of Hong Kong people born outside Hong Kong.

"I will never forget this, nor forgive the government for what it did," said Ho Hei-wah, a veteran family activist: "It split many families and meant they couldn't live together."

REVERSE MIGRATION

But the sting of separation has eased somewhat since then, given relaxed travel restrictions which allow mainlanders greater flexibility to shuttle into Hong Kong on unlimited short visits.

In 2004, a staggering 147 million passenger trips were made between Hong Kong and the southern Chinese city of Shenzhen.

The queuing time for those seeking Hong Kong residency has halved in some cases to just 2 or 3 years.

At the same time, hundreds of thousands of Hong Kong residents have now moved into the mainland, in search of cheaper and less hectic lives.

"(Hong Kong) feels very comfortable and provided for, but you never feel at home," said Andy Xie, a mainlander who lived in Hong Kong for over a decade since 1995, working as a leading economist for several international investment banks.

"Before 1997, there was a feeling of superiority, because Hong Kong was rich and prosperous, but Chinese cities have caught up fast," said Xie who moved back to Shanghai earlier this year.