Australian screen star Cate Blanchett has persuaded her favourite designer Giorgio Armani to support her Sydney theatre troupe, it was announced Thursday.

The Sydney Theatre Company said Italian fashion icon Armani would become its official patron and make a sizable cash donation described "as one of the largest ever individual financial gifts to a theatre company in Australia."

Oscar-winner Blanchett takes over as the company's artistic director next year in a return to her theatrical roots and Armani made it clear that the star's involvement was a major reason behind his support.

"Cate Blanchett is one of the greatest stage and screen acting talents of our time," Armani said in a statement.

Blanchett, who frequently wears Armani's creations on the red carpet, said the designer was one of the most creative people she had ever met.

"The prospect of the STC embarking upon a creative relationship with an artist of Mr Armani's experience and calibre is not only an inspiring but expansive one," she said.

Armani will visit Australia in November to meet members of the theatre. Local media reports said he would design the costumes for at least one of its productions.