Most couples would settle for exchanging their vows at the altar as proof that they're in it for the long haul.

But Jill Duggar and Derick Dillard went for the "braces and belt" approach to marriage to make it even more difficult to divorce.

Their wedding airs on a two-hour special of 19 Kids and Counting on TLC tonight at 8pm ET.

And the Duggars revealed on their family blog that the show will feature the special Covenant Marriage that Jill and Derick chose to enter into.

Apparently it is an option offered to couples in Arkansas, Arizona and Louisiana which ties them into having to seek counselling prior to marriage and in the event of experiencing marital problems after saying "I do".

The covenant marriage also requires that couples go through a longer period of separation before a divorce will be granted.

Derick's mum Cathy told People.com it was "so special" to be a signatory on their covenant marriage certificate.

"But it wouldn't matter if they chose that type of marriage certificate or not, those two would still have a covenant marriage," she added.

Jill's dad, Jim Bob, revealed to People.com that he and wife Michelle had been praying for their daughter's marriage for 23 years.

"As Jill and I were out in the hallway waiting to come in, I thought about how Michelle and I got married 30 years ago," he said.

"I couldn't hold back the tears thinking I was giving away my daughter. It was an exciting time, but it was also a time of a lot of emotion."

The special broadcast comes just days before Jill's younger sister, Jessa, walks down the aisle to her fiancé Ben Seewald at the First Baptist Church, Bentonville, Arkansas, on Saturday.

Jessa and Ben became engaged on August 14 - their 11-month anniversary – making it the second wedding this year for the Duggar family.

Like her big sis, Jessa has also made the decision with Ben to hold off on their first kiss until their wedding day on Saturday.