Canada-born US senator Ted Cruz has made good on a promise to renounce his birth country's citizenship, amid speculation he could make a run for the White House in 2016.
His spokeswoman, Catherine Frazier, said Cruz's action became official last month and that the Texas senator received written confirmation at his home in Houston on Tuesday. She said the Republican was "pleased to have the process finalised".
Frazier added: "Being a US senator representing Texas, it makes sense he should be only an American citizen."
Cruz, 43, was born in Calgary, Alberta, in 1970, while his parents were working in the oil business there. His mother, Eleanor, is from the US while his father, Rafael, is a Cuban who didn't become a US citizen until 2005.
Though he has been in office only about 18 months, Cruz helped lead last year's partial government shutdown and has become a conservative grass-roots champion.
Amid questions last year about his eligibility to be president should he decide to run, Cruz released his birth certificate to the Dallas Morning News and said he was surprised to find that he had dual Canadian-US citizenship.
Upon learning that he received it at birth, he promised to formally give it up. Months passed before Cruz hired an immigration attorney to help him with the process.
Frazier provided a copy of Cruz's Certificate of Renunciation, which certifies that Rafael Edward Cruz "has formally renounced Canadian citizenship and pursuant to the Citizenship Act will cease to be a citizen".
The US constitution says only a "natural born citizen" may be president. But legal scholars agree the description covers foreign-born children of US parents.