Hilary Duff is proudly back in her skinny jeans eight months after giving birth to her first child.

"Yaaaa bitches! Gabe Johns you're kickin my ass and its paying off! Skinny jeans! lets go!" Duff said as she tweeted a photo of her size 26 jeans.

Johns is a Los Angeles-based personal trainer and boxing instructor who was recruited by Duff to help her shed the pounds two and half months ago, according to his rep.

"Hilary and Gabe have been doing everything from boxing to two-a-day workouts incorporating wind sprints and jump roping in an effort to finally shed the baby weight. Hilary's been steadily dropping pounds each week," Johns' rep told Us Weekly.

Duff, 25, welcomed her first child, Luca Cruz, in March and was criticized for not losing the pregnancy weight a mere three months after giving birth. 

"I'm not perfect, but I feel fantastic," Hilary told In Touch magazine at the time. "This is how it goes for most women - the weight doesn't fall off overnight."

Duff expressed that she would take her time to get her pre-pregnant body back.

"I think if you ask any pregnant mom, they're like 'I want my body back,' but it takes time," she told Us Weekly in June. "It takes nine months for your body to get that way and it's putting on that weight on purpose."

Unlike most celebrities, Duff has taken her time when it comes to dropping the baby weight and that's just fine with her:

"There are some women who look the same right after -- I think they are freaks of nature! I don't know how that happens," she told Parents magazine in October. "I'm not one of those people. It takes your body nine months to get there -- really 10 months. So I'm trying to be patient but I'm working hard. And I think now more than ever, I appreciate my body and what it's done for me."

Duff married her professional hockey player husband Mike Comrie in August 2010. She gave birth to their first child,  son Luca Cruz Comrie, on March 20 this year.