Janet Jackson says that she is now keeping in shape by mixing up her exercise but could not tolerate a harsh trainer.

The singer has recently revealed her svelte new figure as part of her deal with Nutrisystem.

But she tells Us Weekly that her trainer Tony Martinez knows how to achieve good results with her to help her keep the weight off.

"Right now I love running, so I've been doing a lot of running," she told the magazine.

"I can't take someone yelling in my ear bootcamp style. He knows he needs to mix it up and make it different every day.

"He makes sure it's not boring because then I won't want to do it."

Janet, who has dealt with fluctuating weight over the years, says her new eating regime means that she doesn't have to "deprive" herself of things that she loves.

"I eat some of these things and you think to yourself, Oh, I shouldn't be having this!' because it's so good!"

The 45-year-old says that she enjoys Nutrisystem because she gets to each "cookies, cakes and brownies."