AceShowbiz -

New mom Cheryl Cole is shrinking back into shape just three months after giving birth to baby son Bear. The singer's boyfriend, Liam Payne, has revealed that she has lost her post-baby weight almost immediately, even though "she thinks she's massive."

According to Closer magazine, Cheryl has been working out at home with her assistant Lily England's personal trainer boyfriend, Shane Collins. A source has told the publication that "Cheryl didn't want to have people staring at her in the gym or at classes, so Shane goes to her house."

It has also been reported that the 33-year-old singer has stepped up her eating plan in an attempt to lose the weight she gained during her pregnancy. "Cheryl has been on a sugar-free plan, which has helped her enormously, and has managed to wean herself off the chocolate and ice-cream treats during her pregnancy," the source adds.

Liam revealed in a candid radio interview on Capital FM last month that Cheryl still thinks she's "massive." The One Direction member told Nick Grimshaw, "Pregnancy is hard to deal with, it’s that first pair of jeans you can’t get into and she thinks she’s massive but she’s lost everything."