Jessica Simpson plans to make "lifestyle" changes to shed her baby weight

Jessica - who is engaged to Eric Johnson - said: "I think anybody who's gone through a pregnancy, after they have the baby, it's like, 'I need to do something about this.

"For me, I really want to do something that is a lifestyle, because in the past, I've been known to yo-yo diet."

The 31-year-old beauty also insisted she hasn't set herself a target amount of weight to lose, but will measure her progress according to her shape.

She added: "There's not a goal weight - I just want to feel normal and fixate on inches. I really want to set small goals, so I'm constantly reaching goals and not looking at something so far ahead."

Despite gaining a lot of weight during her pregnancy, Jessica insists she ate healthily but indulged her cravings because she wanted to enjoy the experience.

She said: "I was like, 'I'm going to enjoy my pregnancy,' and I did.

"I ate very healthy, but I did indulge some of my cravings and that's okay because I know I can work it off now."

Benedict Cumberbatch has joined the cast of 'Twelve Years a Slave'.

The 'Sherlock' star will star alongside Michael Fassbender and Brad Pitt in the movie which tells the real-life story of Solomon Northup, a black slave living in New York in the 1850s who is enticed to go on a trip to Washington only to end up being kidnapped and sold into slavery.

Benedict will play the plantation owner who buys Solomon (Chiwetel Ejiofor) and is won over by his engineering skills.

Solomon eventually won his freedom when a Canadian man smuggled letters to his wife to lead a court case which eventually saw him released.

Steve McQueen will direct the movie based on a script adapted from Northup's autobiography by British filmmaker Steve and John Ridley.

This will be the third time Fassbender - best known for the role of Magneto in 'X-Men: First Class' - will be working with Steve after appearing in 'Hunger' and sex addiction movie 'Shame'.

Benedict has recently been working on the 'Star Tr! ek' sequ el - which stars Chris Pine (James T. Kirk), Zachary Quinto (Spock) and Simon Pegg (Scotty) - scheduled to hit cinemas in May 2013.