The actress is expecting baby number three in 2021.
The tonic is popular among parents for treating colic.
The Pierce family welcomed two daughters, seven weeks apart.
The celebrity mum has called for people to 'normalise' using baby formula.
'As for me and Jeremy, we'll definitely have our hands full'.
'I was very worried that she was going to have a heart attack.'
The mum-of-one appeared on a preview for the Rachael Ray Show.
'When life cracks you open… let your loved ones in'
"Fertility has been the defining topic for me," she said.
The singer-songwriter proudly captioned the picture 'future voters'.