Credit: AKM Images/Flynet

ScarJo and Sean are playing house!

Three months into their unexpected romance, Scarlett Johansson has moved in to the $3.8 million Malibu home of Sean Penn, an insider tells the new Us Weekly, out Wednesday.

Relocating from her temporary digs at a West Hollywood hotel, the recently divorced 26-year-old "has essentially moved in over the last few weeks," the source says. And now that the actress and Penn, 50, share the same roof after months of furtive sightings at hotspots in Hollywood, Mexico and beyond, "they just stay home" whenever they can.

Among their fave homebody activities? Eating in and hanging out with Penn's kids with ex-wife Robin Wright, who are mere years younger than Johansson: daughter Dylan, 20, and son Hopper, 17.

Plus, the domestic duo love working out (their recent jog fueled pregnancy rumors that proved false), entertaining pals like Owen Wilson and Javier Bardem and more. (Back in February, Us Weekly was first to break news that Johansson had rebounded from her December divorce from Ryan Reynolds with Penn.)

Get all the details on their happy new home life in this week's Us Weekly -- out now.