LONDON - As Rishi Sunak prepared to deliver a major policy speech on Wednesday, the British prime minister received a surprise introduction from his "best friend": his wife Akshata Murty.

The generally media-shy Murty, the daughter of an Indian software billionaire, took the stage at the annual Conservative Party conference just before Sunak was due to speak, telling gathered party members about what drives her husband and joking about his love for romantic comedy films.

While Murty has appeared with Sunak on diplomatic trips this year, including to India and Japan, she has rarely taken centre-stage at a major event.

"The reason why I'm here is really quite simple. And it's because Rishi and I are each other's best friends," she began as Sunak watched from backstage, adding that her own speech was a surprise to her husband.

"We're one team, and I could not imagine being anywhere else than here today, with all of you to show my support to him and to the party."

The couple are the richest ever occupants of 10 Downing Street. Murty is the daughter of Narayana Murty, one of the founders of Indian IT giant Infosys and owned shares in the company worth roughly $600 million as of April.

When Sunak was finance minister last year, he faced questions over his wife's tax status, leading her to decide she would stop avoiding British tax on her foreign income.

"I'm afraid he does love a good rom-com. The cheesier, the better, even," Murty said to applause at the start of her speech. "You'll be relieved to hear that episodes of Emily in Paris are not informing his outlook on the EU."

(Reporting by Sachin Ravikumar; editing by Michael Holden)