Josh Duggar, of 19 Kids and Counting fame, is facing up to 20 years in jail on child pornography charges.
The 33-year-old was taken into custody in Springdale, Arkansas, and pleaded not guilty to the charges at a virtual federal court hearing on Friday.
Homeland Security has brought two charges against Duggar, one count of receipt of child pornography and one count of possession of child pornography.
News of his arrest comes just days after he and wife Anna announced they were expecting their seventh child, a baby girl.
In a statement, parents Jim Bob and Michelle Duggar said, "We appreciate your continued prayers for our family at this time.
"The accusations brought against Joshua today are very serious.
"It is our prayer that the truth, no matter what it is, will come to light, and that this will all be resolved in a timely manner. We love Josh and Anna and continue to pray for their family."
Duggar is a former reality star, making regular appearances on TLC's 19 Kids and Counting when he was younger, but he has stayed out of the limelight after it was reported in 2015 that he had an account for the Ashley Madison cheating website.
He admitted at the time to being unfaithful to his wife and spent six months in a faith-based rehab.
That came around the same time as another scandal when it emerged that Jim Bob and Michelle had turned him over to law enforcement as a teenager for molesting four of his sisters, including Jessa Seewald and Jill Dillard. No charges were filed. The TLC show was cancelled soon after.
Commenting on Josh's arrest this week, Dillard and her husband Derick told People magazine: "We just found out this information yesterday. It is very sad."
Another sister, Jinger Vuolo, posted a statement on Instagram: "We are disturbed to hear of the charges against Josh.
"While this case must go through the legal system, we want to make it clear that we absolutely condemn any form of child abuse and fully support the authorities and judicial process in their pursuit of justice."
Josh is in an Arkansas detention center awaiting a bond hearing.
The judge at Friday's hearing ordered that if he is granted bond, he must live with a third party where no children are present.