Jessica Alba's dog has died.

The 36-year-old actress paid tribute to her ''best friend'', Sid the pug - who appeared in her 2003 movie 'Honey' - and admitted she, her husband Cash Warren and their daughters Honor, nine, and five-year-old Haven are devastated by the pooch's passing.

Jessica - who is pregnant with her third child - share a slideshow of images of Sid and her family on Instagram and wrote: ''Our sweet Sid passed this morning she lived a long life, eating everything she could sniff out, she was my OG Rolldog, made her feature film debut in Honey.

''She was @Cash_warren first dog. Endured millions of snuggles from Havie pie and @shanidarden. She was the best friend a girl could ask for. We went through so much together my Sid. RIP (sic)''

The sad news comes not long after the 'Sin City: A Dame To Kill For' actress revealed she was expecting her third child by posting a video of her daughters holding big number one and two balloons, with the actress holding one that read number three as she displayed a visible baby bump.

She captioned it: ''@cash_warren and I are officially going to be outnumbered #babyonboard #herewegoagain #blessed (sic)''

Jessica is incredibly close to her daughters and regularly takes them with her to work with her to ensure she is never away from them for too long.

She previously explained: ''I go on so many business trips, and they're usually two to three days. I'll bring just one at a time and it'll be like, 'Mom's gonna bring you on a special trip. We'll get to have a sleepover, we'll get to order room service, we'll get to rent a movie. It's really fun!

''I just try to make the time that I spend with them quality. We like to go on walks and we like to watch movies and barbecue. They love to take a bath and then get back in their pyjamas for the rest of the weekend.''