Cheryl has reportedly been putting herself through gruelling workouts to deal with the stress of her comeback.

Despite claiming in a recent interview that since becoming a mother, she no longer cares what she looks like, the 35-year-old singer has allegedly been working out for two hours a day to look her best as she returns to the spotlight.

"She is doing an hour of yoga every morning, and then doing 30 minutes of weights or toning, and then another 30 minutes of cardio and boxing at night," a source told Heat magazine. "She likes to get her sweat on - she says she needs it mentally to shake off her stress."

Cheryl, who recently split from her 25-year-old boyfriend Liam Payne, is looking slimmer than ever thanks to her six days a week workouts, and she is also following a plant-based diet devised by her nutritionist.

"She wants to look the best she can and thinks the petite look really suits her," the insider continued. "Joan (her mum) thinks she could do with putting on a few pounds but Cheryl says that while she's promoting her music she needs to be in tip-top shape."

The former Girls Aloud star dropped the video for her new song Love Made Me Do It, released on 9 November (18), and since then has come under intense scrutiny for her changing look, as fans wondered what she had done to her face.

Cheryl brushed it off in public, saying in an interview with BBC Radio host Nick Grimshaw: "My whole body, even my face, everything's changed since Bear was born."

However, privately, an insider said the attention has been "overwhelming" for the singer - who has admitted to suffering from anxiety since the birth of her son Bear, 19 months.

"She felt it would give her something else in her life," explained the source. "But she forgot how much pressure there is, and it seems to have got worse since she last released music four years ago."