Amber Portwood looked thinner than ever during a weekend appearance at the wedding of her Teen Mom OG co-stars, Catelynn Lowell and Tyler Baltierra.

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Just weeks after revealing she's lost nearly 40 pounds in recent months, Portwood showed off her impressive weight loss progress alongside Lowell, Baltierra, her third co-star, Maci Bookout, and her fiance, Matthew Baier.

"Work it, Amber! On Saturday, Aug. 22, Catelynn Lowell and Tyler Baltierra tied the knot after a 10-year romance. Though all eyes were on the Teen Mom OG bride, many fans couldn’t help but notice that one of her costar guests had significantly slimmed down," Us Weekly reported on Monday. "Amber Portwood attended the Charlevoix, Michigan festivities with her fiancé, Matt Baier, looking trim and healthy."

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In addition to Bookout, Portwood and their significant others, Lowell and Baltierra were also joined by Kailyn Lowry and her husband, Javi Marroquin, when they tied the knot on Saturday, after 10 years of dating and two children together.

On Twitter, Portwood shared the following photo of herself and Baier.

Portwood and the rest of the cast of Teen Mom OG are expected to return to MTV in the coming months for a sixth installment of the reality show. However, at this point, the network has yet to confirm the series' renewal.

Tags: teen mom teen mom og catelynn lowell Tyler Baltierra weight loss Amber Portwood matthew baier MTV Reality TV