Reese Witherspoon’s pregnancy has helped heal her troubled marriage to Ryan Phillippe and brought Hollywood’s golden couple closer than ever, The ENQUIRER has learned.

The couple found out they were expecting shortly after they returned from a second honeymoon in the Caribbean they’d taken in March to help ease tensions in their marriage. In our April 1 issue, The ENQUIRER revealed that the young superstars were struggling to resolve marital problems and deal with Reese’s fears that Ryan was cheating on her.

Their trip to a tropical island with daughter Ava, three-and-a-half, bolstered their sagging relationship — and now the out-of-the-blue baby news has revitalized their marriage.

“They didn’t know it at the time they left for the Caribbean, but Reese was already pregnant,” a close friend of the stars revealed. “They’ve been trying for another baby ever since they moved into their new Bel-Air mansion this past spring, but Reese hadn’t been able to become pregnant.”

Shortly after returning from the Caribbean, Reese became suspicious she was pregnant and contacted her doctor, who sent a nurse over to the house to draw her blood. Shaken by the hormone surges of early pregnancy, the 27-year-old actress reacted emotionally to the visit.

“When the nurse pulled out the needle, just the sight of it seemed to send Reese into in a mini-meltdown and tears flowed down her face,” the friend said. “After a good cry, Reese let the nurse take her blood. Then she took a long walk by herself in the canyons near her home.”

Reese has been going full steam since she finished “Legally Blonde 2,” which came on the heels of “Sweet Home Alabama.” In a few weeks she’ll begin her next film, a remake of the 19th Century period classic “Vanity Fair.”

“She told a friend she had a mini-breakdown because with the baby coming, everything seemed to be happening at once,” the friend said. “She’s been stretched thin this past year with the remodeling of her home, her work, her marriage, and taking care of daughter Ava and three dogs.

“But after the news of her pregnancy at last sunk in, she’s bounced back entirely to her old self. And now she and Ryan are closer than ever.”

The pal said medical confirmation that she was pregnant forced Reese to move up all her upcoming projects so that she can finish them in advance of her expanding waistline.

The baby is due in November.

“She’s talking about the names she’s picked out for her next child,” said the friend, “but the only trouble is they’re all girl’s names, so I don’t know what will happen if she has a boy.”