Pregnant Jessica Simpson: 'I won't eat everything in sight'

Jessica Simpson, who's pregnant with her second child, says she won't "eat everything in sight" this time around, and will try to limit excessive weight gain.

"[I gained] a lot more than doctors would recommend [last time]," Simpson, 32, said on the "Tonight Show" Jan. 15. "I was really happy to be pregnant and I didn't ever step on the scale. I didn't realize you could gain that much weight that quickly."

The 5-foot-3 Jessica, who tipped the scales at over 200 pounds during her first pregnancy, admits she gained too much weight by overeating, and promises not to repeat that mistake. "I didn't really make any good, healthy decisions," Simpson confessed.

Jessica lost 70 pounds six months after giving birth to daughter Maxwell in May 2012, only to turn around and become pregnant again. While she's happy to be expecting again, she says it wasn't planned.

"Apparently it was a part of God's plan for my life," says Simpson. "I was extremely shocked because I was going through a lot of hormonal changes, trying to get back to the old, vibrant Jessica. You know, it was kind of like a one-night stand. And it happened, all over again!"

Pregnant or not, Jessica Inc. continues to profit, as she's preparing to roll out a new sitcom based on her life. Simpson will play herself but is casting actors to play her father and fiance Eric Johnson.

"We don't have a name yet, we're just now in the process of casting everyone, doing the pilot," she says. "I will be playing myself but we'll have actors playing Eric and my dad. That'll be funny."

In addition to her upcoming TV series, Jessica stars on the reality TV competition "Fashion Star," and is a rep for Weight Watchers under a $4 million deal. In 2012, Simpson's self-named clothing line grossed $1 billion.