The couple had recently purchased a huge plot of land near Los Angeles where they will build their new love nest, reported Showbiz spy.
"Justin and Selena are building a massive home together in Tarzana. It's just a dirt lot right now with some pipes, but it has a gorgeous panoramic view of the San Fernando Valley," a source said.
Selena's mother lives in the surrounding Woodland Hills area and both Bieber, 19, and Gomez, 20, spend most of their free time in the urbanised valley.