Serena Williams wasn't sure she could love her second child as much as her first

She told People: "Olympia was a solo child. She was our star. And I am so obsessed with Olympia. Even when I was pregnant, I was like, 'How do I even love anyone as much as Olympia? It just doesn't work.'

"It's so funny how, I don't know, just your heart gets bigger. I was just like, my heart just got bigger."

Serena also admitted that whilst her eldest is a "hard act to follow", her youngest seems to be managing well and has become such a "tough little cookie" even at her early stage in life.

She said: "Olympia is a very hard act to follow, but I tell you what, Adira has followed it and it's just so crazy. She's amazing. I just can't wait for people to see how amazing she is in her own way. And she's so special and she's so tough. She's just a tough little cookie. And she reminds me a lot of me in that aspect."

Serena previously admitted that there was "a lot of pressure" on her from her eldest while she was pregnant, who was hoping to end up with a little sister.

Asked about the adjustment of going from one child to two, Serena she told Extra: "My baby kept saying, she's like, 'I want a sister! I want a sister!' So, that was also a lot of pressure - is it gonna be a girl or a boy, you know? But no, I always wanted a family, a big family, but we'll see."