The former Congress MP was admitted to hospital on April 27 and discharged on April 29. His leg ligament hurt because of which he could not work properly.
Rajesh's former wife Dimple is taking care of the actor and both his daughters regularly call on him.
Khanna's son-in-law, Akshay, shared the news of the new ad with his fans on Twitter.
"Showcasing a treat for you guys very shortly, a humble gesture from a doting fan for his SUPERSTAR Pa-in-law, stay tuned...You will be the first to witness this beautiful commercial of my legendary father-in-law. Not only do I love him but I am also a true fan!! ( sic)," he posted.
The 70-year-old actor's health had been a matter of concern in the recent past.
Despite his ill health, the actor recently shot for the television commercial, by film director R Balki.
A time there was, during the Seventies, when Rajesh Khanna's films were a veritable gold mine for distributors. Girls and women used to swoon on the matinee idol and send him letters written in blood. The decline in his film career came with the advent of the angry young man, epitomized by Amitabh Bachchan in Zanjeer.
Rajesh Khanna joined the Congress and became its MP, but soon got disillusioned. His health has been taking a downturn because of his drinking habits.
Though looking frail and a pale shadow of himself, the 70s superstar's debut ad performance has managed to create quite a buzz with many hailing it as a clutter breaking campaign – and of course, puns galore, on switches and fans.
A media report said Rajesh Khanna has reportedly earned about Rs 55-60 lakh for the Havell's brand endorsement deal.