Josh and Anna Duggar of '19 Kids and Counting' Expecting Baby No. 3

Jim Bob and Michelle Duggar of TLC's "19 Kids and Counting" are expanding their family again/

The couple's oldest son Josh and wife Anna Duggar announced Monday, that they're expecting their third child. The new addition will join the couple's elder children, daughter Mackynzie (3) and son Michael (21 months).

"It is very exciting," Josh told People magazine. "It's fun for Michael and Mackynzie being so close in age and this baby will be, too. We feel very blessed and happy."

The expecting father later shared his happiness on Twitter.

"We're expecting our 3rd child!" he wrote. "We're excited and blessed!!!"

Josh and six-month pregnant Anna want to keep the gender of their unborn baby a surprise until birth.

Well-wishers of the Duggar family welcomed the news: "Congratulations on baby #3. My 9yo daughter is a huge fan of your show & is so happy for you," one of the messages read. "You should name your baby Mikayla if its a girl! :D" another one suggested.

"19 Kids and Counting" portrays the life of Jim Bob and Michelle Duggar and their 19 children. When the series started in September 2008, the couple had only 17 kids and they welcomed their 18^th kid Jordyn-Grace Makiya (4), Dec.18, 2008 and 19^th child named Josie Brooklyn (3) a year later in December 2009. In November 2011, Michelle announced her 20^th pregnancy. However, she lost her child after a miscarriage.

"Josh and Anna are great parents," 47-year-old Jim Bob told People magazine. "It is neat to see their family expanding. I remember those days when Michelle and I went from one to three because we had Josh and then we had twins. It is a great start."