First comes engagement, then comes adoption! Sean Penn has filed to adopt his fiancée Charlize Theron’s 3-year-old son Jackson, sources reveal in the new issue of Us Weekly.

And his bride-to-be couldn’t be more ecstatic.

“Sean always knew that to truly earn a place in Charlize’s heart, connecting with Jackson was one of the most important parts,” a pal close to the Gunman star, 54, tells Us.

The couple, who have been dating for over a year, got engaged while on a trip to Paris this past November. And while they haven’t secured a wedding date yet, they’re still planning on forever together.

“There is still talk of adopting again and giving Jackson a brother or a sister,” the insider adds of the husband-and-wife to-be.

Penn was previously married to Madonna and Robin Wright and is already dad to daughter and model Dylan, 23, and son Hopper, 21.

For more on Charlize and Sean’s plans to expand their brood, watch this week’s Hot Stuff video, as explained by Us Weekly online deputy editor Justin Ravitz and What’s Your Emergency star Michael Urie

Other stories in the roundup: Kate Beckinsale and Chris Evan’s wild karaoke night, Bruce Jenner’s plan to speak out about his transformation, and more!