It marks the first time the actress has confirmed the name and gender of her child.

The ‘Silver Linings Playbook’ star admitted it was “scary” to talk about becoming a mother after friends warned her that she may not “fall in love right away” with her baby, but she said as soon as she gave birth it felt like it was “day one of my life”.

Jennifer, who shares her boy with her husband of three years Cooke Maroney, 38, said they decided on the name Cy after the post-war American painter Cy Twombly, who is one of her gallerist husband’s favourite artists.

She admitted to Vogue: “I remember walking with one of my best friends at, like, nine months, and being like, ‘Everyone keeps saying that I will love my baby more than my cat. But that’s not true. Maybe I’ll love him as much as my cat?’… the morning after I gave birth, I felt like my whole life had started over. “Like, now is day one of my life. I just stared. I was just so in love. I also fell in love with all babies everywhere.

“Newborns are just so amazing. They’re these pink, swollen, fragile little survivors. Now I love all babies. Now I hear a baby crying in a restaurant and I’m like, ‘Awwww, preciousssss.… .’

She added about loving her husband more: “My heart has stretched to a capacity that I didn’t know about. I include my husband in that… I mean the euphoria of Cy is just – Jesus, it’s impossible. I always tell him, ‘I love you so much it’s impossible’.”

She admitted she found herself thinking about the recent overturning of Roe Vs Wade while expecting, saying: “I remember a million times thinking about it while I was pregnant.

“Thinking about the things that were happening to my body. And I had a great pregnancy. I had a very fortunate pregnancy. But every single second of my life was different. And it would occur to me sometimes: What if I was forced to do this?”

She also spoke of her worries about gun violence in America, saying: “I’m raising a little boy who is going to go to school one day. Guns are the number-one cause of death for children in the United States. And people are still voting for politicians who receive money from the NRA

“It blows my mind… we are allowing our children to lay down their lives for our right to a second amendment that was written over 200 years ago.”