Natasha Hamilton has said her teenage son was violently attacked on the school bus because she has been labelled a "4×4 mum".
The former Atomic Kitten had son Josh with Fran Cosgrave, son Harry with Gavin Hatcher, Alfie from her marriage to Riad Erraji and Ella with Ritchie Neville, from whom she has recently split.
The "4×4 mum" slur refers to having four children by four different fathers.
Speaking on ITV's This Morning, she said: "Only two days ago my son was set-on on a school bus and held down and was being shouted at. My eldest son, Josh, he's 13.
"And they were saying, 'Oh your mum's a 4×4´, and things like that. And that just breaks my heart because he was so upset."
She told host Ruth Langsford and guest host James Martin: "Cruel comments are tough for me to read, but as an adult, and being in the industry for many years, I just have to put on my armour and get on with it.
"But now it's trickling down, and the children are on social media, they read magazines, they read comments."
Struggling to hold back tears, the 33-year-old said: "I refuse to let that tag define me, because I have been successful in my own right since I was 16.
"I've worked hard, I've put food on the table and supported all my children, I don't have handouts, I don't have benefits because I earn good money.
"And I actually do the best that I possibly can for my children, so it really makes me angry that people get so upset that I've had four children. Well yeah, I have - and what would my life be without them? It would be absolutely rubbish."
She also highlighted a double-standard, saying that the fathers of her children - and other male celebrities who father children by different women - do not face the same level of criticism.
"They don't get any comments, really," she said. "Especially when me and Rich split up, it was all aimed at me, which is so frustrating.
"Take Hugh Grant for instance, he had two children in one year to two different women, and I'm sure he's a brilliant father, that's none of my business, but that kind of like oh well yeah that doesn't matter."
The pop star also revealed she is still living with Ritchie, despite the split announced in March.
She said: "We still live together, which can be difficult at times, because it's all raw, it's hard to move on when you're still together.
"But honestly, we wake up in the morning and I'm like, 'Do you want a cup of tea?' And we play with Ella together and take her out.
"It didn't work for us, but we are totally dedicated parents for Ella."