Mariah Carey's pregnancy happened ''the hard way.''

The 'Fantasy' singer will celebrate the first birthday of her twins - Moroccan and Monroe - with husband Nick Cannon at the end of this month, and looking back on her pregnancy she admits it was a difficult time.

She told Shape magazine: ''Pregnancy was probably the best and the hardest thing I'll ever go through.

''I know for a lot of women, it can be wonderful and relatively easy. But for me, it was like 'Okay, honey, do you have to do everything the hard way?'''

Mariah lost 40lbs after the babies were born and has since shed another 30lbs, through following a strict diet, and now realises eating the right foods is the key to healthy weight loss.

She added: ''I used to be able to slim down just by exercising more, but that's changed. Since having the babies, I realise that 90 percent of losing weight is my diet.''

As well as being the twins' birthday on April 30, it is also the couple's wedding anniversary and TV presenter Nick has confirmed they will renew their marital vows on the day and promised the twins will be involved.

He said: ''We get married every year; it's our thing. I just have to keep doing it to make sure it's real!

''It's gonna be big. So it's a family day. We'll celebrate with them during the day and just the two of us at night.''