Looking good, Amber Portwood!

The 25-year-old "Teen Mom" star recently tweeted that she's lost 36 pounds, also showing off her flawless skin in a selfie on Monday. And, according to Amber, she's not even done yet slimming down.

"36 lbs down and 15 more to go...almost at my goal," she wrote of her mission to lose a total of 51 pounds.

WATCH: ETonline Catches Up With 'Teen Mom' Stars Amber, Farrah and Catelynn

When asked how she was able to shed the impressive amount of pounds, Amber tweeted, "Cut out bad carbs like sugar and cut down on pasta to start...also try to not eat trans fats." She also revealed that the weight loss took her about four months, though she "fell off for a couple weeks."

It's great to see Amber looking so healthy and happy these days, given her troubled past on the hit MTV show. The Indiana native was memorably arrested for domestic violence against her ex Gary Shirley -- who's the father of Amber's daughter Leah -- with the controversial incident documented on camera. She also spent 17 months in jail in 2012, after being arrested in December 2011 for possession of drugs and failing to complete a court-ordered rehab program.

Amber is now engaged to her fiance, Matt Baier. The couple made an appearance at the MTV Movie Awards in April, where she also showed some leg posing in a white minidress next to her fellow "Teen Mom" stars Farrah Abraham and Catelynn Lowell.

PHOTO: Farrah Abraham's Daughter Gets $100 Bills From the Tooth Fairy

Earlier this month, "Teen Mom 2" star Jenelle Evans exclusively told ET that she recently called off her engagement to Nathan Griffith, with whom she has one child with -- 1-year-old Kaiser. Jenelle also has a son, Jace, from a previous relationship with her ex, Andrew Lewis, which "Teen Mom 2" viewers will remember from past episodes.