19 Kids and Counting star Jill Duggar congratulated her sister Jessa Duggar on her engagement to boyfriend Ben Seewald via Instagram on Friday, Aug. 15 Credit: Courtesy Jill Dillard

Sibling love! Jill Duggar congratulated her younger sister Jessa Duggar on her engagement to boyfriend Ben Seewald hours after the news was revealed via Instagram on Friday, Aug. 15.

"Congratulations on your engagement @jessaseewald @ben_seewald!" Jill, 23, captioned a picture of the future spouses. "We are so happy for y'all! #benseewald #jessaseewald."

As previously reported, 19 Kids and Counting's Jessa, 21, and her boyfriend Seewald, 19, announced they got engaged after 11 months of dating on Aug. 15. "We are so blessed to be engaged!" the couple said in a statement. "God has written an amazing story through our courtship, and another chapter has just begun! We are thrilled to see what the future holds — especially the wedding bells!" 

One day earlier, Jessa posted a letter via Instagram that she received from her husband-to-be as they celebrated their "11th monthiversary." The fifth oldest of the Duggar family also showed off her new pearl necklace that he gave her.

"These elegant pearls looked quite majestic when I picked them out," Seewald wrote in his note. "These pearls were lonely…just like I am when we're apart; but not anymore. I love you my precious princess!" 

Jessa is in good hands when it comes to wedding planning. Sister Jill recently tied the knot with fiance Derick Dillard back in June.