NEW DELHI, Feb 28 (Reuters) - The Reliance-Disney India merger has attracted Nita Ambani, wife of Reliance boss Mukesh Ambani, back into mainstream business as the new company's chair, where her experience in arts and sports, and ties with Bollywood could come in handy.

Reliance and Disney said on Wednesday they would create a $8.5 billion TV and streaming juggernaut in India, setting the stage for fierce rivalry with likes of Japan's Sony, Netflix, and Amazon's Prime Video.

Nita Ambani's appointment at the helm comes just months after she quit the parent entity, retail-to-telecoms group Reliance Industries' board "to devote her energies and time to guide" the group's philanthropy venture.

Her decision to take the role is a strong signal "that this (media) business is close to the family's heart," said a person familiar with Disney-Reliance deal talks.

Sports, especially cricket, is one area where the merged entity and Nita Ambani, 60, have overlapping interests.

Disney and Reliance have separately spent billions on TV and streaming rights for key cricket tournaments over coming years. And Nita Ambani owns the Mumbai Indians team in the Indian Premier League (IPL), the world's richest cricket league.

Shailesh Haribhakti, who is board chair at several Indian companies and has interacted with her in the past, said she was an apt choice to lead the board having worked for years on Reliance group initiatives including sports and education.

"She has the ability to get things done. The way she treats people, gets everyone motivated. She can delegate and take accountability," Haribhakti said.

Born to a Gujarati family, Nita Ambani grew up in a Mumbai suburb and started training in traditional Bharatnatyam dance at the age of six. She married Mukesh Ambani in 1985 when working as a school teacher and has three children who are heir to the Reliance empire.

"I believe as much in the magical powers of sports and education," she said in a speech in 2018, adding she wanted to make "the right to play, right to sports, a reality to all."

Nita Ambani is also a member of the International Olympic Committee and an honorary trustee of The Metropolitan Museum of Art in New York, though most of her work at Reliance over the years has focussed on the group's philanthropic initiatives.

The media business, according to a second source familiar with the deal talks, "piques her interest." (Reporting by Aditi Shah and Aditya Kalra Editing by Mark Potter)