"My husband [Daniel Giersch] actually found some really cute books about explaining to your kid about the baby that's coming and the mommy being pregnant and what goes on with the mommy and then what happens when you bring the baby home," the expectant Rutherford, 40, told PEOPLE Thursday at The Sylvania ShowHouse holiday lights event. "It's really helpful."
While her pregnancy has already had a big impact on her daily life, Rutherford doesn't see it impacting the fate of her character on GG, Lily Bass.
"I told [the writers] pretty much as soon as I found out, so they had some time to think about it," she says. "But they have so many great storylines going right now. I think they decided to go with [them]. I'll only be I think about six months pregnant when we go on hiatus so it shouldn't be too difficult to figure out and work around it."
Rutherford isn't the only Gossip Girl cast member making headlines. Over Thanksgiving weekend, costars Ed Westwick and Jessica Szhor were spotted smooching while waiting for a flight in Dallas.
"I've got a scene with Ed tonight," Rutherford joked. "I'm gonna give him a hard time about it. I love it. I love hearing gossip."
Plus, she adds, "Everyone's very friendly on our show, so they could have taken a picture of them kissing each other good-bye, or giving each other hugs. Or congratulating each other. Who knows?"
Green HolidaysA big fan of the holidays, Rutherford – who uses organic products in her home – told PEOPLE about some of her favorite ways of making her celebrations a little greener.
"I don't have as much time to entertain anymore," she says, "but I do think the holidays are such a wonderful time to get together with friends and family. And you can do it an eco way."
Rutherford's tips: beeswax candles, which don't contain petroleum products, and reusing old gift-wrap and paper bags to wrap small gifts and party favors.
She also recommends you "bring in leaves, pine cones ... and use them instead of paying for plastic ones. You can bring some nature into your home."