Funny lady ... Jennifer Aniston is pregnant with triplets in the Smartwater ads.

Funny lady ... Jennifer Aniston is pregnant with triplets in the Smartwater ads.

Actress Jennifer Aniston is pregnant with triplets - for a funny new TV commercial with comedian Jimmy Kimmel.

The satirical US commercial for Glaceau Smartwater starts with American Idol host Ryan Seacrest presenting a news story about leaked home security video from Aniston's house, which features the actress taking off a stomach-flattening pad to reveal a bulging belly.

Lifting her shirt to expose her baby bump, she asks her unborn kids, "How are my little triplets doing?"

Kimmel makes an appearance in the video as Aniston's grown-up son in a scene around a backyard swimming pool, which is being filled with bottles of the water.

Aniston is also later seen revealing the secret to her picture-perfect hair as she removes a wig to show her 'real' dark locks.

The advert was designed to poke fun at persistent tabloid rumours suggesting that Aniston, who is engaged to Justin Theroux, is pregnant.

Aniston has been a spokesperson for Smartwater since 2007.

Watch the commercial below.