Brad Pitt and Angelina Jolie wanted kids, and they wanted them fast.
The couple already holds the land speed record for celebrity family expansion. And now we know their secret.
A well placed Pitt-Jolie source confirms suspicions that the couple used in vitro fertilization to conceive their newborn twins Knox and Vivienne.
"They both desperately wanted more babies soon," the source said.
Jolie used the procedure, which costs about $12,000 a pop, so "she wouldn't have to deal with the stress of trying to get pregnant," the source said. "She could just knock it out."
Jolie has openly stated that she wants more kids while her and Pitt are still young enough to cope with raising them.
"If we're going to have 10 kids, we'd like to raise them while we're young," the actress told British Elle last year.