"(I have) never been so tense actually while cutting a cake. Thank you everybody for this gesture. It's really touching," Tendulkar said in a brief cake-cutting ceremony where his wife Anjali was also present.
The veteran batsman said it was his former teammate Anil Kumble's wishes that helped calm the nerves. "While walking to get here, I met Anil Kumble along the way who wished me 'Happy Birthday' and told me, 'don't worry, 40 is just a number.' So that was sort of relieving," he said with a smile.
Thanking his billions of fans worldwide, Tendulkar said it was because of their good wishes that he could continue playing more than two decades after his international debut.
"Let me take this opportunity to thank all the people in India and all across the world who are well-wishers of mine...They have supported me and showered their unconditional love on me over the last 23 years. So it's been really special," he said.
"It's because of their good wishes and prayers that I am standing here in front you all after 23 years. It's been my strength. I thought this was the best opportunity to come here and thank each and every one of them for every little thing that they have done for me," he added.
Tendulkar said there have been many special people in his life who have made various sacrifices for him. "There have been so many people who have made various sacrifices, fasting and those kind of things when I was injured... I just want to say thank you which I believe is not enough. "I would have personally liked to meet and thank them but it's not possible so I thought this was the best forum where I could reach out to most of them," the Master Blaster said.
Dressed in a formal charcoal black shirt, the Mumbai Indians batsman cut the customary cake while wife Anjali in a white salwar kameez was beside him in a special programme organised by his IPL franchise.
Tendulkar got the first bite of his birthday cake from Anjali's hands who giggled after being called from the backstage by the batsman on the insistence of the present journalists and photographers. "Now, don't ask her to put it on my face next," joked the veteran cricketer.
The Mumbai Indians senior-most batsman is later scheduled to cut a 40-pound specially-ordered cake at the Eden Gardens ahead of their 8pm IPL match against Kolkata Knight Riders.
In a career spanning 24 years, Tendulkar has got almost all the batting records to his name other than Brian Lara's Test highest of 400 not out.
Tendulkar, who has called it quits from the ODI format to prolong his Test career, has a colossal 18426 runs from 463 matches with 49 hundreds at an average of 44.83. In the leading run-getters list of Test matches, Tendulkar is sitting on 15837 runs with 51 hundreds and an average of 53.86, way ahead of South African veteran Jacques Kallis who with 13128 runs is the only playing batsman to be in the race at fourth place.
Tendulkar has played only one T20 for India as he has limited his Twenty20 ambition to his franchise Mumbai Indians in the IPL.