Natasha Kaplinsky gave birth to a baby boy The newsreader, 36, gave birth to her son, who has not been named, at a London hospital at 8.30am.
She began her maternity leave a month ago, just months after joining Channel Five news from the BBC.
Her husband Justin Bower, an investment banker, and Ms Kaplinsky married in August 2005 following a whirlwind romance.
The couple said in a statement: "We're absolutely thrilled."
Kaplinsky moved from the BBC in February to become the new face of Channel Five news, in a deal reported to be worth £1 million a year.
Her first broadcast attracted one million viewers, almost double the usual audience.
But in April she confirmed she was three months pregnant.
Since first being selected to present the early morning news bulletins at ITV Meridian in 1997, she has worked for ITV London, Sky News and BBC Breakfast before moving to the station's Six O'Clock News.
At Five, Ms Kaplinsky replaced Kirsty Young, who now presents Crimewatch on BBC1 and Desert Island Discs on Radio 4, at Five.
Selina Scott has launched a legal battle accusing the channel of age discrimination, claiming it backed out of a presenting deal to cover Ms Kaplinsky while on maternity leave because she is too old.
Isla Traquair has been unveiled as the presenter of the 7pm bulletin.
Copyright Speakers Corner 2017