"I'm like an alcoholic. It is like, I don't care if I cry, I don't care if I am fat, I am just going to do it for one more week, one more month, and then when I see how much good it is doing her and I can't stop," she told Britain's Style magazine.
"It is a very powerful thing, you know," she added.
The 'Frida' star admitted that breastfeeding is very painful.
"Let me tell you it is tough. You don't know what pain I am in after two hours, how difficult it was at first," she added.
Moreover, she also dismissed claims that it helps mothers shed their post-pregnancy weight.
"And by the way, the myth that says you lose all this weight when you breastfeed? That is so not true! It's like, please, will everyone stop telling me I look really well," she added.