Megan Fox says her stepson is ''indifferent'' to her new baby boy.

The 'This Is 40' star - who gave birth to her first child Noah in September - has revealed her husband Brian Austin Green's 10-year-old son Kassius, from his previous relationship with actress Vanessa Marcil - is not particularly excited about their new arrival because he is too busy playing computer games.

The 26-year-old actress told the Daily Mirror newspaper: ''Kash is a little indifferent. He's not experiencing any sort of jealousy or competitiveness, but he's not excited because he just wants to go play video games.''

But the brunette beauty revealed that former 'Beverly Hills 90210' star Brian is a great father.

She gushed: ''My husband is amazing. He does more work than I do and he's just a champ... He's so helpful and nurturing and amazing...He's my soul mate.

''I love [motherhood]. It's what I've wanted to do since I was a little girl.''

Megan recently revealed becoming a mother has changed her approach to her work because she is mindful of how it could affect him when he is older.

She said: ''It changes your perspective about being overly sexual in a film when you have a baby. I'm going to be more cautious about choosing films because I'm already thinking about when he's in school and his friends are going to be showing him my photo shoots with me in a bikini and he's going to be horrified. So that will deter me from making some of the choices I made before.''