Megan Fox's morning sickness was so bad she worried she was expecting a ''vampire baby''.

The 'This Is 40' actress gave birth to her first child Noah in September and Megan - who is married to Brian Austin Green - joked she was so sick during part of her pregnancy that she compared it to fictional character Bella Swan's ordeal in 'The Twilight Saga' when she was pregnant with a half-vampire tot.

Speaking on 'The Tonight Show', she told Jay Leno: ''It was so bad for me, actually, I was convinced that I was, like, maybe birthing a vampire baby like the one from 'Twilight'. You know what happens to Bella, where she's in cold sweats all the time?

''I felt like that was happening because I had no vitamins and nutrients and I was just nauseous.''

However, Megan, 26, recently revealed becoming a mother has left her happier than she has ever been before.

She said: ''The whole thing has been overwhelming because I didn't know you could love something so much, and I know people always say that but I love him so much it hurts, and it's an interesting feeling to have because I never felt that before.''