"I have been diagnosed with swine flu for which the treatment is underway. With God's grace and good wishes from all of you, I will recover soon," he said on Twitter in Hindi.
According to sources at AIIMS, the BJP leader was admitted following complaints of chest congestion and breathing issues.
He reached the hospital at around 9 pm and is admitted in the old private ward of the hospital.
A team of doctors are monitoring his condition under the supervision of AIIMS director Randeep Guleria, they said.