"Wonderful effort by Shri Anil Ambani, who cleaned the area around Churchgate station in Mumbai along with his friends," Modi tweeted.
The prime minister said said Ambani had invited actors Amitabh Bachchan, Hritik Roshan and Nagarjuna, sportspersons Mary Kom and Sania Mirza, writers Shobha De and Prasoon Joshi, journalist Shekhar Gupta and members of the Runners Club to join the campaign.
"I hope they join Swachh Bharat Mission and inspire others to do so."
The Reliance Group chairman was seen wielding a broom along with fellow members of the Runners' Club to clean the area in downtown Mumbai.
The prime minister had launched the campaign Oct 2, Mahatma Gandhi's birthday, and since then it has been widely propagated and practiced across the country.
Ambani was among nine eminent people like cricketer Sachin Tendulkar, actors Salman Khan, Priyanka Chopra and Kamal Haasan, yoga guru Ramdev and Congress leader Shashi Tharoor, picked by the prime minister to propagate the "Swachh Bharat" mission.
"I am honored to be invited by our respected Prime Minister Shri Narendrabhai Modi to join the 'Swachh Bharat Abhiyan'," Ambani had said in a statement. "I dedicate myself to this movement and will invite nine other leading Indians to join me in the 'Clean India' campaign."