After just three months of dating, Scarlett Johansson and Sean Penn are living together, according to UsMagazine.com. The 'Iron Man 2' actress has moved into Penn's $3.8 million Malibu home, a source close to the couple tells the magazine.

The 26-year-old actress "has essentially moved in over the last few weeks," the insider said. And now that they are living together, the pair are keeping their public outings to a minimum, preferring to "just stay home" when they can.

The source claims Johansson and Penn, 50, like spending their time cooking and staying in with Penn's kids with ex-wife Robin Wright: daughter Dylan, 20, and son Hopper, 17. They also like hanging out with palls Owen Wilson and Javier Bardem.

The couple made headlines earlier this week when Johansson was photographed jogging alongside Penn with what looked like an ever-so-slight belly. Pregnancy rumors quickly started though the actress' rep shot them down quickly.