Actress Jennifer Aniston is reportedly set to become an aunt - her younger half-brother's partner is pregnant.

Alex Aniston, known to pals as A.J., was recently photographed leaving a Los Angeles medical clinic with his girlfriend Adriane Hallek, who was clutching an ultrasound photo purportedly showing their unborn child.

The young couple has yet to comment on the baby news or their relationship, but model and make-up artist Hallek tells the National Enquirer, "He's a great guy, but I don't want to talk about him. He likes his privacy."

A.J. is the son of veteran actor John Aniston and his second wife, Sherry Rooney.

If the baby news is true, the baby will be John's first grandchild.