The baby will be 21-year-old Jacqueline's first child, while Dan, 23, already has an eight-month-old son Teddy, with his ex-girlfriend Megan Tomlin.
The couple released a statement via their spokesperson, which reads: "We're thrilled by our news."
"Becoming a father has been the most amazing thing to ever happen to me," adds Dan. "I can't believe I'm going to be dad again - I'm truly blessed."
A spokesperson for EastEnders offered their congratulations to the mum-to-be, who plays Lauren Branning.
"Everyone at EastEnders is thrilled for Jacqueline," the rep said.
Jacqueline and Dan have had an on off relationship for the past year, and finally confirmed they were together in July, when Dan revealed he was in love with Jacqueline in an episode of The Only Way Is Essex. Romantic!
Dan was being quizzed by his mates Arg, Elliot and Tom, about his relationship with Jacqueline and when asked if he was in love, he replied:
"Yeah I would definitely say I was in love and I don't believe in throwing that word around, but I am happier than I've ever been."
Before news of Jacqueline's pregnancy broke, Dan spoke about how becoming a father has changed his life.
"Having Teddy changed my perspective, he makes me want to do better, and be better," the reality star told Heat magazine.
"I want him to be proud of me... I'll make sure he has everything he ever needs. Having a baby really changes the way you think about everything."