A crossover no-one saw coming.

That's how many in India are describing Microsoft founder and philanthropist Bill Gates' appearance in the iconic Hindi TV drama with actress and former federal minister Smriti Irani.

Mr. Gates appeared on Thursday night's episode of Kyunki Saas Bhi Kabhi Bahu Thi (Because the Mother-in-Law Was Also Once Daughter-in-Law) to talk about maternal and child health with Irani.

The Gates Foundation has been working on curbing infant and maternal mortality for years with governments in Uttar Pradesh and Bihar - the two northern Indian states with huge populations that are also among the most disadvantaged regions.

Government data shows a significant improvement in maternal and child health indicators over the years, including in the two states. But in a country steeped in patriarchy, challenges remain.

Experts say messaging becomes extremely important to keep the drumbeat going to change norms and to make people more aware of the need to take care of their girls and mothers.

And to do that, Mr. Gates perhaps couldn't have chosen a better platform than Kyunki Saas Bhi Kabhi Bahu Thi.

Initially launched in July 2000, the series had a successful run with thousands of episodes broadcast almost daily before it was discontinued. However, it returned for its second innings 25 years after it first hit the screens.

Indian audiences found the show riveting, based on the complex domestic relationship between Irani's character Tulsi and her mother-in-law. The titular character has transformed over the years but continues to deal with contemporary issues alongside traditional melodrama.

The four-minute segment with Mr. Gates kicks off with him greeting Tulsi in American-accented Hindi, setting a friendly tone. Gates and Irani share insights on the importance of maternal health, underscoring the message – when mothers are healthy, children thrive.

The show's makers have stated that they aim to spotlight critical issues through storytelling, with Gates set to appear in additional episodes.

This unexpected cameo has sparked a significant resurgence in interest for the series, fostering a conversation about social issues and engaging viewers like never before.