Kourtney Kardashian may act a surrogate for her younger sister.

The 33-year-old reality TV star - who shares son Mason, three, and daughter Penelope, nine months, with her boyfriend Scott Disick - has offered to be a gestational carrier for her sister Khloe, 28, who has been struggling to get pregnant with her husband Lamar Odom for three years.

She made the generous offer on a new episode of 'Kourtney & Kim Take Miami', which airs in the US today, after overhearing Khloe discuss her infertility problems with their step-brother Brandon Jenner. Kourtney is seen consulting Scott and her doctor about the possibility of carrying Khloe and Lamar's baby for them before telling her sister: 'I was overhearing you talking to Brandon and Leah.

'You were telling them that you don't know if your body can carry a child or something - that if one treatment doesn't work then you won't be able to. So I just wanted to say that if you did need someone to carry your child that I would volunteer my services. I would do that for you... I called the doctor. I got all the info.'

Khloe laughs off Kourtney's offer but later tells the camera: 'I think it is very sweet that Kourtney offers to have my baby in her small uterus!'

The 'X Factor' USA host has been very open about her struggles to conceive a child with Lamar, who has two other children from previous relationship. She was previously forced to deny allegations that she was very upset when her sister Kim announced she is pregnant with her boyfriend Kanye West and will give birth in July. Writing on her blog, she said: 'I'm happily married to a wonderful man and fall in love with him more and more each day, and we'll have a baby when god wants us to and when the time is right.'