A mother gave birth on the side of the Eastern Freeway this morning, after failing to reach a hospital before her baby boy arrived.

Angela and her partner Shane were on their way to the Royal Women's Hospital, but their baby just couldn't hang on.

Angela's waters broke just five minutes into the journey forcing Shane to pull over at the Doncaster exit, near Balwyn, and deliver little Alexander on the front seat of the couple's Holden.

A Seven News camera crew happened to stumble upon the scene just moments after the birth.

The new dad told Seven News reporter Emily Angwin he literally caught his little bundle of joy as he was being born.

"We thought we'd have plenty of time," Shane said. "We jumped onto the off ramp and this is as far as we made it."

The 27-year-old said Alexander was born, wailing and crying, all in five minutes, and described the situation as 'intense'.

"Shane looked a little pale and shocked, but over the moon," Emily said.

Little Alexander weighed 3.9 kilograms and he and mum are doing really well as they recover at the Royal Women's Hospital.

"She's pretty good. We're all just in shock," Shane said.