Sean Penn and Charlize Theron are reportedly planning baby no. 2 together, after the "Gangster Squad" actor filed papers to adopt the 3-year-old son of the "Mad Max: Fury Road" actress.

In a report from Us Weekly, Sean Penn allegedly wanted to take his relationship with Charlize Theron to another level.

"Sean always knew that to truly earn a place in Charlize's heart, connecting with Jackson was one of the most important parts," the source said.

"There is still talk of adopting again and giving Jackson a brother or a sister," the source added.

Sean Penn and Charlize Theron reportedly engaged in November last year during their trip to Paris where he proposed. However, there's no wedding date yet.

In an interview with Extra TV, Sean Penn begged off from revealing the wedding details with his fiancée.

"I can't even say things out loud. I just hate looking at people on television talking about their relationships," he said.

But he did say that he's very happy with his love life right now. "I can't imagine why... she and I have been very, very longtime friends. We hit a speed bump and must have lost our minds, so here we are," he added.

Charlize Theron in a previous interview claimed that she's always wanted a family, so the rumor that she and Sean Penn are looking at baby no. 2 is not quite surprising.

Talking about the adoption process, the South African beauty said: "It took two years of waiting, and then one day, it's finally there, and it feels exactly how it's supposed to feel. I don't know how to describe it. It just feels right."

Prior to hooking up with Charlize Theron, and their reported plan to have baby no. 2, Sean Penn already has two children, Dylan, 23, and Hopper, 21, from a previous marriage to Robin Wright.