They only announced their plan to serve overseas with a Christian mission a little over a week ago but Jill Duggar Dillard, husband Derick and baby son Israel have set off on their new adventure.

Jill's sister Jessa, 22, shared a photo on social media of the young couple boarding a plane on Sunday afternoon with Jill carrying their son in a sling.

She said Jill, 24, and Derick, 26, were 'so excited' to be finally heading to the mission field after 'praying about and working towards this transition since late last year.'

Leaving: Jill, Derick and baby Israel were seen boarding a plane on Sunday in this photo shared via Instagram by Jill's sister Jessa Seewald

Apart from Jessa's post, there's been nothing from the Dillards themselves announcing that Sunday was the day of departure.

Aside from posting a first anniversary wedding album on their website dillardfamily.com there's been no updates from the devout couple since Derick wrote about their decision to go overseas.

Their departure wasn't mentioned via social media by any other family members either.

One year and counting: Jill Duggar, 24, and Derrick Dillard, 26, celebrated their first wedding anniversary on June 14. Alongside a sweet pic of them kissing, Jill wrote: 'The longer I'm married to you the more I fall in love'

On June 26, Derick wrote: 'God has put a desire in our hearts to serve Him internationally for longer than the typical short-term mission trip.'

'Earlier this year God brought about an opportunity much earlier than either of us was expecting.'

The announcement came just three weeks after Jill came forward as one of her brother Josh Duggar's molestation victims.

It was revealed in May that when Josh was a teenager, he fondled five girls including sisters Jill and Jessa before the family started their reality series.

TLC suspended 19 Kids And Counting on May 22 after Josh publicly apologized for having 'acted inexcusably' when he was aged 14 to 15.

At the end of May, Derick abruptly left his job with Walmart and acknowledged that there were 'unknowns' he and Jill would face by choosing to leave the US especially with such a young child.

New life: While Derick has said the couple had been thinking and praying about Christian service abroad for several months, the decision to leave the US came just weeks after Josh Duggar's molestation scandal broke

Tearful admission: Just three weeks ago Jill, along with her sister Jessa, revealed that they were two of their brother Josh Duggar's molestation victims

The couple, who married in June 2014 and welcomed their son in April, have consistently said they want to serve others.

'We have a deep love and care for all of the world and a real passion for those in the nations, as many have even seen in the early stages of our relationship, and our hope is that all peoples of the world would come to repentance and put their hope in the Lord, Jesus Christ,' Derick has written

He added that moving abroad 'is the best option' for his family.

'We look forward to this adventure and the joy of serving Him in this new way. We wanted to share this with you and ask for your prayers as our family makes this transition,' he said.

The couple's blog post includes a link where supporters can donate to the family ministry.