The Swedish Royal Family confirmed the exciting news via their social media channels on Thursday.
Prince Carl Philip, 37, and Princess Sofia, 32, are already the proud parents to a son called Prince Alexander, Duke of Södermanland, who will turn one next month.
Alongside a touching family photo of the trio, the statement read: "The birth is expected to take place in September 2017."
"No changes in the schedule of The Prince Couple's public engagements are planned during the spring and summer of 2017," it concluded.
The same day the pregnancy was confirmed, the Swedish Royal Family banded together to make a glittering appearance for an official dinner at the Royal palace in Stockholm.
Just a hint of Sofia's baby bump could be seen in her deep-red gown, which she teamed with an understated tiara, a silver clutch and a blue sash.
The doting couple adore their son and have taken to parenthood with ease.
Speaking to Swedish publication Svenskdam last year, Sofia described being a mother as "amazing."
"He is very sweet and well-behaved. He’s a mixture of us both," she said of her son.
"The first time does take some adjustment. But it’s still absolutely amazing and wonderful," Prince Carl Philip agreed.
Prince Carl and Princess Sofia's love story is a truly modern tale that gives Princess Mary and Prince Frederik a run for their money.
After meeting through mutual friends Carl Philip, Duke of Värmland has been with former glamour model and reality star Sofia Hellqvist since 2010.
While eyebrows were raised over Sofia's former jobs, which include starring in the 2005 dating show Paradise Hotel and racy photo shoots, this pair prove that your past does not define your future.
Flashback! Watch Sofia as a reality TV star in the player below. Post continues after the video...
On June 13, 2015, the stunning couple tied the knot in Stockholm's Royal Palace chapel in a lavish ceremony.
It marked the first time a Swedish citizen became a princess in over a hundred years. Sofia has now inherited the title Princess Sofia of Sweden, Duchess of Värmland. "It shows Sweden is a warm country with lots of love,” a proud Prince Carl remarked on his wedding day.
Congratulations to the Swedish Royals, we can't wait to meet your new bundle of joy.