Julian Assange's wife Stella 'elated' he is set to be freed

Julian Assange's wife Stella said on tuesday she was "elated" and it was "incredible" her husband was set to be freed following a 14-year legal battle.

Assange, 52, has agreed to plead guilty to a single criminal count of conspiring to obtain and disclose classified U.S. national defense documents, according to filings in the U.S. District Court for the Northern Mariana Islands.

The deal marks the end of a legal saga which has seen Assange spend more than five years in a British high-security jail and seven holed up in the Ecuadorean embassy in London.

"I'm just elated," she told BBC Radio.

"He will be a free man once it has been signed off by the judge and that will happen sometime tomorrow," she said speaking from Sydney, Australia, where Assange is expected to head after he appears in a courtroom on the Pacific island of Saipan.

She said she had flown to Australia on Sunday with the pair's two children, aged 7 and 5, and had told them there was a "big surprise" coming but that she hadn't been certain of what would happen until the last minute.

"It's been so touch-and-go, we weren't really sure until the last 24 hours that it was actually happening," she said.

She said she didn't want to say too much before the U.S. judge signs off on the deal.

"It's just incredible. It ... feels like it's not real," she said.