PM Lee thanks those who sent him birthday greetings for his father Mr Lee Kuan Yew

Mr Lee Kuan Yew celebrating his 91st birthday on 16 September 2014 with current and former staff. (Seated, from left) Education Minister Heng Swee Keat and Singapore Press Holdings chief executive Alan Chan, who served as Mr Lee's principal private s
Mr Lee Kuan Yew celebrating his 91st birthday on 16 September 2014 with current and former staff. (Seated, from left) Education Minister Heng Swee Keat and Singapore Press Holdings chief executive Alan Chan, who served as Mr Lee's principal private secretary. (Standing, from left) Ms Tan Lai Kheng, Ms Linda Chia, Ms Lilian Ho, special assistant Anthony Tan, former principal private secretaries Leo Yip and Chee Hong Tat, private secretary Wong Lin Hoe, Ms Florence Tan, press secretary Yeong Yoon Ying and former principal private secretary Andrew Tan.  -- PHOTO: FACEBOOK PAGE OF HENG SWEE KEAT

SINGAPORE - Prime Minister Lee Hsien Loong has thanked those who wrote to him to wish his father, former Prime Minister Lee Kuan Yew, Happy Birthday.

The older Mr Lee turned 91 on Tuesday.

In a Facebook post on Wednesday, PM Lee thanked well-wishers and said: "Am touched by your warm messages (and the pictures some of you posted), and will show them to my father when I get home."

In the past week, there has been an outpouring of support online for the elder Mr Lee, with tens of thousands of people sending him birthday greetings on Facebook or clicking "like" on posts about his birthday.

As for the Prime Minister, he is at the tail-end of a week-long trip to southern China and is expected to return to Singapore on Thursday.

The family had celebrated the elder statesman's birthday early on Sept 6 at the home of PM Lee's younger brother, Mr Lee Hsien Yang, who chairs the Civil Aviation Authority of Singapore.

The younger Mr Lee told The Straits Times that he and his two siblings, which includes his sister Lee Wei Ling, director of the National Neuroscience Institute, and some of their children marked the occasion with a dinner for their father.

"We have done so for many years, initially with me cooking a simple dinner. As the family grew in size, I have outsourced the catering," he said.

The younger Mr Lee is known to bring in renowned chefs to cook gourmet meals for his father's birthday celebrations.

On the day of his birthday, Tuesday Sept 16th, the elder Mr Lee went to his office, had his usual Chinese lessons and in the evening, he celebrated with a cake in the company of some of his former principal private secretaries, personal assistants and other staff.