Natalie Portman donated $1,000 to The Ellen DeGeneres Wildlife Fund after the comedian correctly guessed the gender of her second baby.
The 36-year-old actress welcomed her second child, a daughter called Amalia, with her husband Benjamin Millepied in February last year.
But when Natalie appeared on the 'The Ellen DeGeneres Show' back in December 2016, the 60-year-old comedian made a bet with the actress that she would be having a baby girl - which turned out to be correct.
Natalie was a guest on the TV show on Tuesday (02.13.18) and revealed she has "kept good" on the bet, despite hinting she may have known the gender of her baby.
She said: "I maybe did, but I maybe didn't want to tell everybody in the world. I still made the bet, because I thought it would show either way.
"But I kept good on my bet. Ellen bet $1,000 ... You were confident, you were right to be confident, it's a girl!
"So I donated to The Ellen DeGeneres Wildlife Fund, which is amazing that you are doing that."
The 'Black Swan' star and Benjamin - who married in California in 2012 - are already parents to six-year-old son Aleph.
And during her most-recent pregnancy, the Academy Award-winning actress revealed that people were kidded into thinking she was due to give birth any moment because of her diminutive figure.
Natalie explained: "It's weird because I'm a small person in general, so you show a lot faster and a lot more when you're small."
In fact, Natalie had to reassure people that she wasn't on the cusp of giving birth.
She said: "Everyone thinks I'm about to pop and about to give birth any minute, and I have months to go ... I went to the store the other day to buy water and the guy at the checkout counter was like, 'Almost, huh?' I was like, 'No! Not at all!"