Dhanush was "aghast" at the idea of endorsing a beauty soap, but actress Sonam Kapoor, his co-star in "Raanjhanaa", managed to persuade him.
On Tuesday, the unconventional-looking hero flew into Mumbai after a flash promotional trip to Chennai to promote his new Tamil film "Maryaan", and shot an ad for Lux with Sonam.
A source from the set said: "Initially, Dhanush who is extremely self-deprecating about his looks was aghast at the idea. 'How can I endorse a beauty soap?' he argued. But it was his new buddy in Mumbai Sonam who convinced Dhanush to give it try."
The "Raanjhanaa" pair shot for the ad amidst loads of bantering and rejoicing, now that "Raanjhanaa" has been declared a hit.
"It was different experience, but fun for me," said a shy Dhanush.
"Raanjhanaa" director Anand L. Rai was also present during the shooting of the ad.
"I just looked at the two of them proudly. When we began shooting 'Raanjhanaa', everyone wondered what kind of a pair Sonam and Dhanush would make. Now they've been unconditionally accepted as an onscreen couple," said Rai.