Ashlee Simpson Embarks on Strict Exercise Regime

Ashlee Simpson has embarked on a strict diet and exercise regime to avoid gaining too much weight during her pregnancy.

The 'Pieces of Me' hitmaker -- who recently confirmed she was expecting her first child with new husband Pete Wentz -- has already gained 20lbs and is so conscious of putting on more weight that she has hired her sister Jessica's former trainer Mike Alexander.

A source reveals, "She's still clinging to the hope that she can limit her total weight gain to no more than 30 to 35lbs. So she is doing low-impact exercises, such as riding the stationary bike and Pilates."

Ashlee, 23, is also refusing to consume any alcohol throughout her pregnancy and, when out for dinner recently, even sent back a pasta sauce because it contained vodka.

The source added, "Ashlee isn't touching a drop of alcohol. She drank before she knew she was expecting, so now she is being over cautious."

Ashlee and Pete announced they were expecting their first child soon after their secret wedding ceremony at her parents' home on May 17.