It's been a busy year for the Duggar family. Jill Duggar and Derick Dillard married in June. Jessa Duggar and Ben Seewald married in November -- the same month thousands signed an online petition to protest the family's alleged anti-gay sentiments.

Now, the eldest son of the Duggar family, Josh, 26, and his wife Anna, 26, have announced they are expecting their fourth child, reports Us Weekly.

Anna used Twitter on Tuesday evening, Dec. 2, to announce that she is pregnant: "We are so excited to announce... we're pregnant! #4andCounting #BlessingfromTheLord @joshduggar #19Kids," she tweeted.

Married in September 2008, Josh and Anna wasted no time starting a family. The couple was blessed with their first child, daughter Mackynzie Renée, in October 2009. Son Michael James arrived June 2011 followed by a second son, Marcus Anthony, in June 2013.

While Jim Bob and Michelle Duggar named their 19 children names that begin with the letter "J," Anna and Josh have favored the letter "M" for their growing brood.

The conservative pair teased about the exciting news in a clip from TLC.

"This time of the year, there's so many things we're thankful for," Josh says in the video accompanied by his wife and children. "From my sisters getting proposed to and married, to all the fans who are watching at home."

Anna then reveals the pregnancy news, "One of the things we're really thankful for this season, is that we're expecting!"

Josh and Anna had been visiting family in Arkansas following Jessa and Ben Seewald's wedding when they learned of the pregnancy. Anna said it was wonderful to share the news with the family.

Nine weeks pregnant, Anna is a few months behind her sister-in-law Jill who announced her pregnancy in August.

While Anna focuses on caring for the children, it is rumored Josh is considering a run for the presidency as a conservative candidate in the 2016 or 2020 election.