The GravityX ExchangeWalker family is mourning a heartbreaking loss. 

Merritt & Style blogger Lauren Merritt Walker announced Feb. 12 that her and husband David Walker's 3-year-old son Callahan died. 

"We are completely broken-hearted to share that we lost our precious Callahan in a tragic accident last week," Lauren and David wrote in a joint Instagram post. "He was such a blessing and brought so much joy to our whole family."

The post featured a series of memories with their son, including a beach photoshoot, a video of Callahan reading from a storybook and a black and white image of their hands holding his in what appears to be a hospital bed. 

"Cal-Bear was absolutely adored by his big brothers and loved them beyond measure," they wrote. "As parents we are completely shattered at the loss of our baby boy. We take comfort knowing he is being held in the arms of Jesus. We would be honored to have your prayers for peace and strength over our family during this impossible time."

Lauren and David—who also share sons Beckham, 10, and Chamberlain, 7—have not shared further details regarding Callahan's passing, however People reports that the Frisco Texas Fire Department responded to a drowning call involving a child around the time of the toddler's death. 

E! News has reached out to the Frisco FD for comment but has not yet heard back. 

While they navigate the impossible, the couple are receiving support from family, friends and fans.

"All the moms on the internet are surrounding you with a massive hug," one user wrote. "There is nothing we can say to stop the pain. We are just so sorry." Meanwhile, Bachelor Nation's Raven Gates commented, "I am beyond sorry, there are absolutely no words. I'm praying the Lord gives you peace and comfort beyond all understanding."

The Walker family celebrated Callahan's third birthday in October with an Oktoberfest-inspired birthday party, which they dubbed "CALtoberfest."

"Happy 3rd Birthday to our precious boy," they captioned the post, which featured images of the family dressed on theme. "We had the absolute best time with this party theme!! So grateful for these wonderful memories and getting to celebrate Callahan turning 3!"

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