The 37-year-old, who headlined a Teenage Cancer Trust charity gig at the Royal Albert Hall this week, took the socialite to a restaurant to celebrate after the show, reported Sun Online.
And the couple, who had their first date last week after Brand filmed his 'BrandX' TV show at London's Duchess Theatre, are planning to carry things on when Martin, 29, is next in LA.
"Russell and Zara really hit it off when they met through pals this year and swapped numbers. She came back to his hotel after a late night at the Albert Hall on Thursday morning. She has travelled to LA a lot for work over the years and they have planned to hook up when she is over next," a source said.