Beverley Mitchell and Haylie Duff are both pregnant. Credit: Tiffany Rose/WireImage

Bump buddies! Former 7th Heaven costars and longtime pals Haylie Duff and Beverley Mitchell are now pregnant together. 

Duff, 29, shared a photo with her good friend via Instagram on Thursday, Jan. 22, in honor of Mitchell's 34th birthday that day. 

"Happy birthday to one of my besties/sister @beverleymitchell," she captioned the shot. "The kindest friend, the best mother.. Love you #PreggoTogether."

In the sweet image, Hilary Duff's older sister places her hand on Mitchell's growing baby bump. With her ombre-highlighted hair pulled back and in loose waves, Duff shows a slight hint of her own bump in a plunging black top over black pants. 

Mitchell, who announced that she is expecting a baby boy this past fall, wears a white top over white pants with a black blazer and a statement necklace. She also shared the picture from her own Instagram account.

The star, who played daughter Lucy Camden on 7th Heaven, is already the mother of daughter Kenzie, 21 months, with husband Michael Cameron. She married the accountant in October 2008. 

This will be the first child for Duff and her fiancé Matt Rosenberg. The happy couple planned to wed in the coming months, but the actress, who played 7th Heaven's Sandy Jameson, told Us Weekly that the nuptials are on hold until the couple's lives quiet down. 

"It was kind of too much to all do at once," she told Us. "I'm shooting my cooking show Real Girl's Kitchen and he's working... We're just trying to focus on one thing first, and then we'll do it."

Duff and Mitchell aren't the only 7th Heaven alums with growing families. As Us Weekly revealed, their costar Jessica Biel is also famously expecting her first child with husband Justin Timberlake. The three stars reunited in February 2013, when Duff and Biel, 32, fêted Mitchell at the baby shower for her first child.