Turns out she was joking.
After the 42-year-old made the bold statement in an interview with Entertainment Tonight, many publications caught on to report the story.
The actress then tweeted: "You guys realise I was joking about breastfeeding Bella until she is 6, right?"
You guys realize I was joking about breastfeeding Bella until she is 6, right?— Alyssa Milano (@Alyssa_Milano) September 9, 2015
Milano, is mum to Milo, four, and Elizabella, one.
Now if she joked about breastfeeding her daughter until she was 13, we would have cottoned on.
But her tweet lead to many other mums arguing that actually, breastfeeding a child until he/she is six isn't a huge deal.
@Alyssa_Milano apparently this country has lost it's sense of humor. so what if you did? you raise your kids, i raise mine. how it should be— Lance Holeman (@MorbidTheClown) September 9, 2015
@Alyssa_Milano I nursed my son until he was 3 years and 3 months.— Lisza M Hayward (@1c72bbaa880143c) September 9, 2015
@Alyssa_Milano breastfeeding is so healthy I breastfed my second baby till she was 2, do it as long as baby wants too— Brooke (@DKAMomma) September 9, 2015
@Alyssa_Milano it's possible, some do, I didn't but to hell with anyone who says you can't (even if you weren't serious).— Rosemary A. Blodgett (@RosemaryAubry) September 9, 2015
Previously, mums have spoken out about breastfeeding their children beyond toddler age.
Mum Denise Sumpter opened up earlier in the year about how she still breastfeeds her six-year-old daughter.
She said: "I'll feed Belle as long as she asks. I don't know how long that will be. It will be the same with my son Beau. I don't think there's anything weird about it."
The 44-year-old said she truly believes her children have benefitted from having her breast milk for longer, adding: "There are things I get out of it - like calm, happy children.
"But I can say with certainty I've done this entirely for the benefit of my kids."
Milano has always been open about breastfeeding, posting photos of her feeding her daughter, Elizabella, to Instagram.
Her most recent post was on her daughter's birthday.