Page Six has learned that the auburn-tressed Oscar winner is pregnant with her third child and will give birth next summer. The happy news comes as Roberts flies high in the nations No. 5 picture, Charlottes Web, in which she provides the voice for the beloved spider. Her pregnancy is somewhat of a surprise since the star, 39, had so much difficulty with her first effort to start a family with cameraman hubby Danny Moder, 37. In November 2004, she gave birth to twins Phinnaeus Walter and Hazel Patricia - but only after months of round-the-clock bed rest that followed a scare in which she was rushed to the hospital with false labor. Its not known how the Georgia-born beautys pregnancy will affect her latest screen projects. Roberts, who commands up to $25 million per movie, is appearing in Mike Nichols new flick, Charlie Wilsons War, and has reportedly signed to do The Friday Night Knitting Club. But its likely shell take some time off, as she did when the twins were born. Its a joy being domestic. Its something I want and something that makes me very happy, she once told an interviewer. Moder and Roberts tied the knot in July 2002 at their sprawling ranch in Arroyo Seco, N.M., near Taos, after hed dumped his makeup-artist wife of five years, Vera Steinberg, and Roberts had shed her longtime boyfriend, Benjamin Bratt. Whether Roberts upcoming visit from the stork will be her last is anybodys guess. She once told Oprah Winfrey that she and Moder wanted a big family, adding: Im in the harbor of my life . . . Danny has really shined the light for me. Roberts bliss is eons away from the old days when she was a swinging bachelorette with such boyfriends as Kiefer Sutherland, Liam Neeson, Matthew Perry and Daniel Day-Lewis. There was also a blink-and-youll-miss-it marriage to Lyle Lovett.