Sam Worthington's wife Lara Bingle Worthington has reportedly given birth to their first child.

The 38-year-old actor ''couldn't be happier'' after he and the 27-year-old model, who recently confirmed they secretly got married following wedding rumours late last year, welcomed their baby into the world this week.

A source close to the 'Avatar' star told UsMagazine.com: ''The baby was coming any day for the last week. Their families came in and they've been staying at his place... Sam couldn't be happier.''

It is not yet known whether the tot is a boy or a girl.

Speculation first began swirling that Lara was pregnant in December and she was frequently spotted showing off her growing baby bump in Los Angeles and New York City.

The Australian beauty recently insisted that parenthood wouldn't change their jet-setting ways.

She said: ''Settling [down] doesn't mean being in one place. For me, it's about being settled in yourself. I like travelling and I like the life [Sam and I] have. I don't want to be pigeon-holed.''

The duo started dating in September 2013 and a source previously said: ''They're inseparable. They've been making steps in their relationship but he's an extremely private guy.''