Singer Celine Dion has spoken publicly for the first time since her husband Rene Angelil died, paying tribute to him at a memorial service in Las Vegas.

The pop star said he kept her grounded and protected her from the gritty business details of her superstar career.

People gathered to celebrate the life of her husband and manager credited with striking the deals that have defined her status as one of the world's most popular voices.

"He protected me from day one to for the rest of my life, I am pretty sure of that," she said.

Angelil died on January 14 after a long battle with throat cancer. He was 73.

Born in Montreal to a Canadian mother and Syrian father, Angelil was a former singer-turned-manager who discovered a 12-year-old Dion and mortgaged his house to finance her first album.

He guided her career for most of her life, most critically as she learned a new language to sing in English to become an international success.

To underscore his influence, long-time friend Paul Farberman said at the memorial that the Titanic deal was far from certain when Dion was first approached to sing the movie's theme song. She rolled her eyes when she first heard it played on the piano.

"It didn't look like this was going to be a big success story," Mr Farberman said of the movie. "And I'll never forget how Rene literally stood up from the table and he said 'I'm a gambler, and I'm going to bet on this one.' And of course, the rest is history."