Kristen Bell's five-year-old daughter Delta is ''still in diapers''.

The 'Frozen 2' star has revealed her youngest daughter - whom she has with her husband Dax Shepard, with whom she also has seven-year-old daughter Lincoln - is not potty trained, despite her older sister transitioning from diapers to the toilet in record time.

Speaking on her 'Momsplaining' web-series, Kristen said: ''My oldest daughter at 21 months, we merely suggested that she use the toilet in the other room. [She] never wore another diaper beyond that. And we were lying in bed giggling, my husband and I were like, 'Why does everyone make a big deal out of this potty training? It's so easy. Just tell the kid to use the toilet.'

''Currently, my youngest is five and a half, still in diapers.''

But the 39-year-old actress has insisted there's nothing wrong with Delta, as she added: ''Every kid is so different.''

Meanwhile, Kristen recently hit out at sexism when it comes to parenting, as she said her husband Dax Shepard never gets asked about how he copes with both his career and his life as a father, but she is always questioned about balancing motherhood and her acting career.

She said: ''Like, with my job, when I get interviewed and people say, like, 'How do you balance it all?' I don't think anyone has ever asked my husband that question. 'How do you balance it all, working and being a dad?' Everything's geared towards moms though. That's the thing. Just the idea that you have to fit into these gendered boxes, like, my husband is in love with cars. He loves them. He loves them more than me. But, I know some stuff about cars.''