Congress president Rahul Gandhi turned 49 on Wednesday and Prime Minister Narendra Modi was one of the first political leaders to greet him on his birthday.
In his response, Gandhi thanked Modi and said he appreciated the prime minister's greetings.
A host of Congress leaders and workers also wished Gandhi, as he met many of them at the party headquarters in New Delhi on Akbar Road. Some leaders also wished Gandhi in Parliament.
Modi took to Twitter to convey his birthday wishes to Gandhi.
"Best wishes to Shri Rahul Gandhi on his birthday. May he be blessed with good health and a long life," he tweeted.
Gandhi replied on Twitter, saying, "Thank you for your greetings narendramodi ji. I appreciate them."
The two leaders were locked in a bitter war of words in the run-up to the Lok Sabha polls, in which the Bharatiya Janata Party-led National Democratic Alliance returned to power with a massive majority.
Gandhi earlier met his mother and UPA chairperson Sonia Gandhi at her residence and later arrived at around 10 AM at the Congress headquarters where party leaders and workers gathered in large numbers to wish him.
Gandhi received flowers from his partymen and offered them sweets.
Among those who wished him at the AICC office were former prime minister Manmohan Singh, his sister and Congress general secretary Priyanka Gandhi Vadra and Leader of Opposition in the Rajya Sabha Ghulam Nabi Azad.
"Thank you all for your best wishes and greetings on my birthday. I'm overwhelmed and grateful for your love and affection," he later tweeted and posted some pictures on the micro-blogging site of him meeting the party leaders and workers.
Calling Gandhi his "good friend", DMK chief M K Stalin took to Twitter to extend his birthday wishes.
Stalin also shared a photo of him shaking hands with Gandhi at a meeting in the past.
"I wish my good friend @RahulGandhi a very happy birthday. I wish you many more years of public service. #HappyBirthdayRahulGandhi," the DMK chief tweeted.
The DMK and the Congress joined hands in February this year to contest the Lok Sabha elections in Tamil Nadu and Puducherry as allies.
Stalin had even proposed Gandhi's name as the Opposition's Prime Ministerial candidate ahead of the polls, but the idea did not cut much ice with Trinamool Congress supremo Mamata Banerjee and Samajwadi Party president Akhilesh Yadav.
Gandhi, who was in a joyous mood, shared some light moments with the workers and media persons at the party headquarters. He also offered sweets to those wishing him on his birthday.
Party leaders said no cake was cut and the celebrations were low key in view of the death of over 100 children due to acute encephalitis syndrome in Bihar.
However, youth Congress workers had put up many hoardings of Gandhi at the party office and elsewhere in the capital.
Rahul was also greeted by many other politicians on social media.
Punjab Chief Minister Amarinder Singh wished Gandhi good health and a long life.
"Wish you a very happy birthday, dear @RahulGandhi. Proud of who you have become over the years; I see my dear friend (late) Rajiv (Gandhi) in you," Singh tweeted.
"May God bless you with a long, healthy and prosperous life," the chief minister added.
'Greetings and good wishes to Shri @RahulGandhi on his birthday. Wishing him a long life filled with good health,' Defence Minister Rajnath Singh tweeted.
'Best wishes on your birthday,' wrote the West Bengal chief minister along with the same wish in Bangla.
Bahujan Samaj Party Supremo Mayawati also penned her wish on the micro-blogging website.
In her Hindi tweet, the former Uttar Pradesh chief minister wished Rahul a long and healthy life.