Jessica Simpson admits she is ''anxious'' to get her body back in shape.

The 32-year-old fashion designer, who gave birth to her son, Ace Knute, via a scheduled C-section in Los Angeles on Sunday (30.06.13), plans to start working out again, as soon as her doctors give her the all clear, because she wants to lose weight before marrying her fiancé Eric Johnson.

The 'Fashion Star' mentor told People magazine: ''Whenever the doctors give me the go-ahead, I'll start training.

''I'm anxious to have my body back for myself, but I have to be patient. I don't know how long it's going to take, but I'm planning on working hard.''

Jessica signed a $4 million deal with Weight Watchers following the birth of her first daughter, Maxwell, 14 months, after gaining 60 pounds during her pregnancy, but was forced to put her contract on hold after unexpectedly becoming pregnant again.

She is expected to resume the position later this summer and admits she can't wait to finally marry her long-term fiancé after being forced to postpone their nuptials twice.

She said: ''I definitely look forward to the day that I can look into his eyes and make that commitment that we both really long for. He's just got to stop knocking me up!''