CATE BLANCHETT - THIRD SON FOR OSCAR-WINNING ACTRESS CATE BLANCHETT

Cate Blanchett has given birth to her third son in Sydney, according to her spokesman.

The actress delivered Ignatius Martin Upton on Sunday, said Tim McKeough, media relations manager at the Sydney Theatre Company.

"All are well and very happy," said Mr McKeough, who represents the theatrical group of which Blanchett and her writer husband Andrew Upton are co-artistic directors.

Ignatius weighed 3.6 kilograms (7.94 pounds) and is Blanchett and Upton's third son, after six-year-old Dashiell, and Roman, three.

Australian prime minister Kevin Rudd issued a statement after the birth, saying: "I want to extend my best wishes to Ms Blanchett and her family and thank her for her contribution to the Australia 2020 Summit thus far."

He explained that the Lord of the Rings star will still attend a summit in the Australian capital Canberra on Saturday, where she, author Julianne Schultz and arts minister Peter Garrett will take part in a Creative Australia panel ahead of the 2020 summit.

Blanchett, an Oscar-winner for her portrayal of Katherine Hepburn in The Aviator, will next be seen as Agent Irina Spalko in the fourth Indiana Jones film.

She stars alongside Harrison Ford, Shia LaBeouf, Ray Winstone and Karen Allen in Indiana Jones and the Kingdom of the Crystal Skull, set for release on May 22nd.