Over the next few weeks, viewers will see Lauren - played by 19-year-old Jacqueline Jossa - begin to realise that the love she feels for her Uncle Derek's son is more than a familial bond.
"This is going to be a huge storyline across the autumn," an EastEnders insider told the Daily Star Sunday.
"Lauren hits the booze and shows her vulnerable side to Joey. He's there for her and feels very protective.
"The more time they spend together the more they start to realise their feelings for each other are not just that of cousins."
As the chemistry between the teenage pair intensifies, they try to hide their feelings from Lauren's parents Max and Tanya and Joey's sinister dad Derek.
"It's a powerful force," the source added. "The attraction is so strong between them that it's going to take something huge to stop them jumping into bed."