null is taking Hollywood by storm following her star-making role in Black Swan, but that doesn't mean she can't still laugh at herself.
The Swan starlet is also mystified about her "Sweet Lips" nickname, courtesy of tonight's SAG winner null...
"I don't know!" Kunis told Giuliana about the origin of the sexy moniker. "Why don't you ask [Natalie]?
"I literally sat at the table [at the Golden Globes] and was like, 'Oh no!' And I paid for it the rest of the night," Kunis told us.
Check out the video above to see whether Mila has her own friendly name for Portman.