The blonde bombshell, 23, is reportedly expecting with her long-term boyfriend Greg Shepherd, who doesn't appear on the ITV2 reality show. Billie is yet to address the rumours on her Twitter page.
"Billie and Greg are over the moon," a source told The Sun. "They've been a couple for two years now and love each other to bits.
"They can't wait to meet their son or daughter in the summer," they added. "All their friends and family – especially her sister Sam – are made up for her."
The source went on to attribute the success of their relationship to keeping it off camera. "Billie and Greg have always been seen as the ideal couple as they get on well and they don't have all the dramas like everyone else on the show."
Meanwhile, Billie's sister Sam is said to be set to enter the Celebrity Big Brother house on Friday night.
The reality TV star was spotted leaving her house with suitcases to cheers from her family.