The Gambia was readmitted to the Commonwealth on Thursday, welcomed back following the democratic election of President Adama Barrow, who reversed a shock pull-out in 2013.
His predecessor Yahya Jammeh suddenly withdrew the impoverished west African nation in October that year, branding the group an "extension of colonialism" as he lashed out at international organisations.
Accused of flagrant rights abuses, Jammeh ruled mainland Africa's smallest country with an aura of mysticism and an iron fist after seizing power in 1994.
Barrow began the readmission process in February last year, two months after topping an election in which Jammeh initially refused to give up his 22-year rule, triggering a crisis.
Barrow's formal application to rejoin the Commonwealth, submitted last month, received unanimous support from member states.
"The Gambia is ready to regain its former glory on the international stage and reiterates its commitment to the fundamental values of the Commonwealth Charter," the Gambian government said in a statement.
"It is the fervent desire of this Government that our membership to the Commonwealth will usher in an era of socio-economic development to complement the government's ongoing efforts, especially for women and youth," it added.
The Gambia's re-entry means there are once again 53 member states in the Commonwealth, the voluntary association of mostly former territories of the British empire.
Setting the seal on its return Thursday, The Gambia's flag was raised in a ceremony at Marlborough House, the Commonwealth Secretariat's headquarters in London.
"The government and people of The Gambia are ecstatic and overjoyed," said Francis Blain, the country's representative in London, as he hoisted the flag.
Under Barrow, "democracy, good governance, rule of law, respect for human rights and the independence of the judiciary have been fully restored," he said.
"Every effort will be made by the government to ensure that functioning of democratic processes in The Gambia are scrupulously maintained."
The Gambia will now be among the countries attending the Commonwealth's biennial summit, to be held in London in April.
"When Gambia left it was a great moment of sadness: sadness for The Gambia, sadness particularly for the Gambian people, so it's a coming home," Secretary-General Patricia Scotland told AFP.
The Gambia first became a Commonwealth member on its independence from Britain in 1965.
It is the fourth country to rejoin having left after South Africa, Pakistan and Fiji. Ireland (1949), Zimbabwe (2003) and the Maldives (2016) are the only other countries to have quit the group.
Asked about the possibility of Zimbabwe returning following the ousting of Robert Mugabe after 37 years in power, Scotland told AFP: "Any member who has left is welcomed home if they wish to commit to the charter and the values (of the Commonwealth), so any member who's left, we're always anxious that they come back."
British Foreign Secretary Boris Johnson, who visited The Gambia to reset ties in February last year, said Thursday: "This shows that when a country commits to strengthening democracy, governance and the rule of law, it is welcomed back to the international community and the Commonwealth family."