She also posted a snapshot of her and Nathan all dressed-up for their dinner date with the caption, "#NoFilter my bestfriend forever and ever ! ?"
Jenelle and Nathan already have one child together, 4-month-old Kaiser, and have been dating for almost two years.
The controversial reality star is also a mother to her now five-year-old son Jace -- who was featured on the MTV reality show -- and Nathan also has a three-year-old daughter Emery from a previous relationship.
But Jenelle isn't the only Teen Mom star with some recent exciting news. Maci Bookout, 23, announced that she's expecting her second child -- this time with her longtime boyfriend Taylor McKinney -- on Dec. 29., and fan favorites Tyler Baltierra and Catelynn Lowell welcomed their second daughter Nova Reign on Jan. 1, after giving their first daughter Carly up for adoption in 2009.