"Birthday greetings to the Congress Vice President, Shri Rahul Gandhi. I pray for his long and healthy life. @OfficeOfRG," PM Modi said in a tweet this morning.
Rahul Gandhi is in Italy on a short vacation to spend some time with his grandmother.
Sources in the party had said they were not sure how long would be Rahul's sojourn, but indicated he would celebrate his birthday abroad with his maternal family.
He last travelled to get his mother Sonia Gandhi back from an undisclosed location, after she had travelled abroad for medical treatment for an unannounced ailment.
The Congress vice president's travel came in the wake of crucial meetings taking place on the presidential election, the process for which will start tomorrow with the issue of notification and start of filing of nominations.
The all-important sub-group of the Opposition leaders would be meeting tomorrow to evolve strategy for the July 17 presidential election.
The Congress party is also planning to "expose" the Modi government for "failing" to fulfil the promises made to farmers by organising an agitational plan jointly with other parties.