Actress Rose Byrne is set to become a mum for the first time, and she's handling her first pregnancy like a pro.

The Bridesmaids star was pictured at LAX yesterday with a noticeable bump, suggesting she's at least four or five months pregnant.

Wearing a red and navy checked shirt-dress over dark tights and black ankle boots, the 36-year-old star looked every bit the relaxed expectant mum.

She tucked her brunette hair into a wide-brimmed brown hat as she made her way through the busy terminal.

So far Rose's maternity style has been all about comfort – soft, flowing fabrics that gently skim her bump.

We love this floral summer dress she sported while strolling through the Chelsea district of New York back in July, during the early stages of her pregnancy:

Although this is the first child for Rose, it's the second time around for her boyfriend of three years Bobby Cannavale – the Will & Grace star already has a 20-year-old son from his marriage to Jenny Lumet.

Rose and Bobby met on the set of Annie back in 2012, and though they kept their romance under wraps for the first year, Bobby couldn't hold his excitement in for long.

"She's the love of my life," he told the audience at the 2013 Emmy Awards.

As for Rose, she doesn't find exclamations of love so easy – but she's trying to get better.

"To be honest, I’m not naturally that much of a romantic person," she told Elle Canada last year.

"I have trouble with things that feel very manufactured, like Valentine’s Day. I’m trying to get better at romance."