The goalkeeper, who is known as Phan Van Santos in Vietnam, has played for the Dong Tam Long An team since December 2001 and can communicate in Vietnamese, fulfilling all the requirements for citizenship.

The 30-year-old from Rio de Janeiro, who is also known for scoring from free-kicks, received president Nguyen Minh Triet's approval on December 25.

Santos told the Vietnam Football Federation's official website, www.vff.org.vn: "I am very happy to become Vietnamese. The new citizenship will help me greatly in my career and maybe national football as well.

"As a professional player, playing on the national team has always been a burning dream for me. I'm awaiting the day when I wear the national team's jersey, which is also an important reason for my decision to become Vietnamese.

"I know it is very difficult but it will be my honour to play for Vietnam."

The landmark decision could pave the way for other sports people to be granted Vietnamese nationality.

Tran Quoc Tuan, general secretary of the VFF, said: "The decision is of great significance to the future of Vietnamese football because it means more international players will be given citizenship."

Santos was allowed by the Brazilian Ministry of Justice to renounce his Brazilian nationality, a prerequisite for getting a Vietnamese passport.

He added that he had long considered Vietnam as his home and hoped to obtain dual nationality if the country's law changes in the future.

"I have been living and working in Vietnam for six years," he added. "I think my decision was the right one, even though it was very difficult.

"I myself felt that Vietnam and its people are close, friendly and aggressive with football, like Brazilians. That stimulated me to make the serious decision."

The goalkeeper has been an integral figure in Dong Tam's recent success. The team won promotion to the top flight in 2003, before winning two straight V-League titles in 2005 and 2006, and a Super Cup in 2006.

Santos' switch of allegiance has received the backing of club officials and team-mates, who support his bid for the Vietnam number one jersey.

Pham Phu Hoa, Dong Tam's executive director said: "Santos is the best goalie in Vietnam at the moment, and his chance of being called for the national team is very high."

Dong Tam captain Tai Em added: "I expect to play with Santos on the national team at the 2008 AFF Cup. Dong Tam will help him overcome the challenges and contribute his best to Vietnamese football."