Natalie Portman appears pregnant at Venice Film Festival premiere

Natalie Portman had gossips giddy at the Venice Film Festival in Italy on Thursday (08Sep16) by debuting what looked like a growing baby bump.

The actress, 35, was in the city for the premiere of her acclaimed new movie Planetarium, and stepped out in a figure-hugging blush pink gown that left many convinced the star is pregnant with baby number two.

There's nothing official, but sources close to Portman and her husband, French choreographer Benjamin Millepied, tell Us Weekly the Black Swan star is a mum-to-be again.

And Natalie didn't appear to be keeping her pregnancy a secret - one bystander tells the publication the actress was rubbing her belly on the red carpet and smiling.

Portman and Millepied, 39, met on the set of Black Swan and wed in 2012. Their son Aleph was born in 2011.

The actress recently returned to Los Angeles after living in Paris for two years while her husband served as director at the Paris Opera Ballet.

She recently told chat show host Jimmy Kimmel she's happy to be back in America, explaining, "Everyone smiles a lot here. It's so nice. They're more cool in France.

"I didn't realise I got used to it until I got here and I was so surprised! I feel there's a lot of rules of politeness and codes of behaviour there (in Paris) you have to follow. It's a lot looser here."

But she confessed she's not always fond of working in Hollywood: "I think Hollywood is many worlds," she told SF Weekly. "The (entertainment industry) is populated by both wonderful and less wonderful people. Depending on your environment, you can definitely feel discouraged or upset by the surroundings. Of course, you can have feelings of superficiality or emptiness or all of that, I think, and want to fill it with meaningless relationships."