Dan, who won Big Brother 10 and finished as the runner-up of Season 14, announced the big news on Valentine's Day on Twitter.
"Both @cgheesling and I are excited for our first baby due this summer!" Dan captioned a photo of the married couple, their dog and an image of the ultrasound. "Thank you guys for all the baby love!"
Chelsea added, "Lots of love in the Gheesling family this Valentine's Day. @DanGheesling and I are adding another member this July!"
Dan is best remembered for receiving all seven jury votes to win Big Brother's tenth season. He then appeared on Season 14 as a coach to the houseguests but was granted permission to play about halfway through the game.
When Dan was up for eviction in Season 14, he brilliantly staged his own "funeral" to gain pity from his peers -- a diabolical plan that actually worked to keep him in the house. However, Dan's ruthless gameplay overall stirred up a very bitter jury and Super Fan, Ian Terry, ended up winning the $500,000 grand prize.