To the boy in the Philippines, his American benefactor and source of kind letters and gifts was known simply as "G. Walker."

To the Christian charity helping him keep his benevolence secret from the world, he was George Herbert Walker Bush – the 41st president of the United States.

Compassion International, which helps poor children around the world through a network of local churches, revealed for the first time this week that the late president, who died last month, had quietly sponsored a Filipino boy named Timothy for 10 years.

The organisation released a number of Bush’s heartwarming letters to his young charge.

"I want to be your new pen pal," Bush wrote in his initial letter sent on January 24, 2002.

"I am an old man, 77 years old, but I love kids; and though we have not met, I love you already," said the former president, identifying himself as a resident of Texas.