Joshua Wong, one of Hong Kong's most famous pro-democracy campaigners, has launched a new political party.
The 19-year-old said his party, Demosisto, would demand self-determination for Hong Kong.
Mr Wong was a leading figure in the so-called Umbrella Movement in 2014, which aimed to secure greater voting rights for the territory's residents.
"Street activism is not enough if we want to fight for a better future," Mr Wong told the BBC.
"We have to enter the system, create a political party and shape the political agenda, in order to drive forward our movement for self-determination."
Although Mr Wong is too young to run for office, Demosisto will put forward candidates in Legislative Council elections in September.
His televised arrest in September 2014 helped spark pro-democracy protests that would continue for 79 days, paralysing the heart of the city.
But they ultimately failed to win any concessions from the Chinese government.
Party 'rejects violence'
Mr Wong recently disbanded his student activist group Scholarism to pave way for the new party.
Its first goal is to contest, and hopefully win, seats in the Legislative Council election in September.
Mr Wong himself, not yet 21, is still too young to run. Three fellow party leaders will stand for election in two districts.
For his part, Joshua Wong says his party rejects violence, but will continue to engage in street politics.
His journey from child activist to party leader has begun.
A founder of student protest group Scholarism, in 2012, Mr Wong rallied more than 100,000 people to protest against Hong Kong's plans to implement mandatory "patriotic education" in schools.
He began his protesting career at just 13, when he demonstrated against plans to build a high-speed rail link between Hong Kong and the mainland.
Two years later, he had set up Scholarism, successfully challenged the government and was firmly in the limelight.
By 2014 his profile was so high, he held a press conference to announce his university entrance exam results.
A former British colony, Hong Kong became a special administrative region of China in 1997.
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