The 36-year-old, who adopted Jackson in March, said that everything before he came into her life is a blur.
"It's strangely everything that you've hoped for and it feels so right. I don't know how else to say it. I feel like I can't remember anything prior to him. I feel like it was always just meant to be what it is," Theron said.
The single parent celebrated her first Mother's Day with her mother and Jackson.
"My mum and Jacks are here with me. We had a nice morning. He got to spend a little time with me and he got to have a little snuggle. I'm going to see them later tonight. It's really nice to have him here," she added.