Liam Neeson (center), with sons Daniel and Micheal, and Joely Richardson on March 22, 2009
08/26/2009 AT 12:05 PM EDT
Liam Neeson and his two sons are "taking each day as it comes" since the sudden death of his wife Natasha Richardson.
Still, the actor and his two sons with the late actress, Michael, 14, and Daniel, 12, "are doing good," Neeson said Wednesday on Good Morning America
"[We are] still getting extraordinary condolence letters from American people. That's deeply, deeply touching," Neeson, 57, told Diane Sawyer.
Neeson also acknowledged the passing of Sen. Edward Kennedy
, whom the actor first met when he was 10 years old during a visit to the Kennedy ancestral Irish homestead. Kennedy was one of those who contacted him following the March death of Richardson, 45.
"He wrote my family a very, very beautiful touching condolence letter when Natasha died," said Neeson. "He was a special man."
Neeson, who is appearing in the new film Five Minutes of Heaven
, says he's been moved by the letters from so many Americans. "[That] is partly the reason that I have recently become an American citizen," says the star who was born in Northern Ireland. "America has been very, very good to me. I am still a proud Irishman ... but I have become an American citizen, and am very proud of that."