Ferne McCann named her daughter after a facial cleanser.
The 31-year-old reality star - who has four-year-old Sunday with former flame Arthur Collins - revealed that she was inspired to name the tot after a "clay mask" beauty product she was using at the time.
She said: "So the name Sunday was because I was using a face cleanser by the brand Sunday Riley. It was like, a clay mask. And I just thought like, you know, like many other make-up and beauty brands with a female first name and second name, you could probably think of some in your head. I just thought that was her name."
The former 'TOWIE' star - who has charted the life of her young daughter on ITV reality series 'First Time Mum' since her birth - went on to explain that other she had considered other monikers but just thought that Sunday was "such a lovely name" when she was using the product.
Speaking on the 'Sam and Billie' podcast, she told her former co-stars: "And I was like; ‘That’s so nice! That is just such a lovely name!' I had others such as Roberta and lots of different ones. I didn’t have any boy names. And when she arrived, I was just like; ‘Yeah’."
Ferne - who is now dating upmarket retail estate agent Lorri Haines - added that the name just felt "so, so right" when she first laid eyes on the newborn.
She said: "Obviously I feel like you’ve got to see your baby’s face and it just felt so, so right."