She's the self-described 'tough cookie' and mother to two Victoria's Secret models, Gigi and Bella.

But Yolanda Hadid has opened up about her battle with an illness which 'brought her to her knees'.

In 2012, the former model was diagnosed with Lyme Disease, an infection caused by bacteria spread by the bite of an infected deer tick.

Scroll down for video

'This disease brought me to my knees': Yolanda Hadid, centre, is mother to supermodels Gigi, left, and Bella, right. and the self-described 'tough cookie' has spoken candidly about her battle with Lyme Disease

'I don't remember what it's like to be normal. I just can't pull it together,' the 52-year-old told Channel Nine's A Current Affair program.

The former Real Housewives Of Beverly Hills star continued: 'I couldn't read, I couldn't write, I couldn't stand in bright lights... I couldn't watch TV because of the sound.

'Life took me to my knees where I was praying and begging to stay alive one more day for my children.'

No definitive treatment or cure for Lyme Disease has been found.

Getting back to good health: After five years battling the disease, the 52-year-old says she is back up to 80 per cent health

'Life took me to my knees': Yolanda said she began to pray to stay alive 'one more day' for her children

Last year Yolanda revealed that Bella and her younger brother Anwar also suffer from the condition.

Symptoms include pain in the muscles or joints, fever, malaise, and chronic fatigue.

Bella's older sister Gigi is the only member of the family who hasn't been affected.

Yolanda says she is now back to 80 per cent health after her five year battle with the illness.

Bella (right) and her younger brother Anwar also have the disease, while her older sister Gigi (left) is the only member of the family who hasn't been affected

Meanwhile, the 52-year-old has been in Australian to promote Channel Nine's new website for women, Honey.

Speaking on the network's morning show, Today Extra, she revealed she didn't want her children to get into modelling at an early age.

'I was always very strict about the fact I never wanted them to work until they were 18,' she told the program.

'I didn’t want anyone judging them on the way they looked.'

'I didn’t want anyone judging them': Yolanda revealed she didn't want her children to model before they were 18 years old. Above, a throwback snap of the family she recently shared on Instagram

Gigi, 21, recently announced that she would be returning to the Victoria's Secret Fashion Show this year, posting: 'See you in Paris!'

Bella, 20, will be making her debut at the show alongside her big sister, who walked in it last year.

Anwar, 17, signed with IMG Models earlier this year - the same agency that reps his older sisters.

Yolanda will share more details of her struggle with her illness in her upcoming memoir, Believe Me: My Battle With The Invisible Disability Of Lyme Disease, due out next year.