Scarlett Shacking Up With -- But Not Knocked Up By -- Sean Penn

Wonderwall, Wednesday, April 13, 2011, 10:55am (PDT)

By Kat Giantis

Three months into their when-dewy-met-grizzly love match, Scarlett Johansson and Sean Penn have apparently made a major commitment: They're sharing personal space.

Us Weekly reports the starlet, 26, has vacated her temporary residence at a Los Angeles hotel and settled into the 50-year-old Oscar winner's nearly $4 million Malibu spread. According to a source, the soon-to-be ex-Mrs. Ryan Reynolds, who listed her Hollywood Hills mansion at a major loss back in February, "has essentially moved in over the last few weeks."

And it appears the smoke-scented honeys, who have progressed quickly from footsy to romantic dinners to south-of-the-border getaways, have already carved out a nice, comfortable couple's rut.

"They just stay home," notes the spy, who says they like to chill with famous pals such as Javier Bardem and spend time with Penn's two kids with ex-wife Robin Wright, daughter Dylan, 20 (who, we should point out, is in the same youthful demographic as her dad's squeeze), and son Hopper, 17.

Cohabiting with a sexy blond actress must be a nice change for Penn, who has spent much of the last year roughing it in earthquake-ravaged Haiti while helping with relief efforts.

No word on when he plans to return to the devastated region, or if ScarJo will share his tent.

Meanwhile, Scarlett and Sean will probably adhere more strictly to their homebody lifestyle after a jog last weekend with mutual pal Owen Wilson sent the rumor mill into high alert.

The reason was an ever so slight bulge seemingly visible beneath Johansson's tank top (see the pics here), which immediately led the Interwebs to declare her knocked up.

Her rep, however, quickly shot down the rumors.

"Scarlett is not pregnant," he insists (via People and Us). "She's outside running, and it's simply the placement of her shirt that is misleading. … She's been training for 'The Avengers' for over four months and is in the best shape of her life."

Unfortunately, her spokesman did not offer an explanation as to why the actress was running in the ugliest shoes known to man.

RELATED: Scarlett takes Sean as her plus-one to Reese's wedding

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