Hugh Jackman's estranged wife Deborra-Lee Furness appeared to confirm the real reason for their September 2023 legal separation stemmed from his rumored affair with his former Music Man leading lady, Sutton Foster.

The Australian 68-year-old's private Instagram account 'liked' an October 26th video from gossip blogger Tasha Lustig claiming he was 'running off with the mistress' and planning a 'soft launch' of their relationship - according to Us Weekly.

Adding credence to the claim was Deborra-Lee's friend Amanda de Cadenet, who commented on the same post: 'You are on point with this one. My beloved friend Deb is about to have her glow up any moment fyi!'

It was in March 2020 - right when COVID shut down the world - when the Australian 56-year-old and the Georgia-born, Michigan-raised 49-year-old giddily first began workshopping Jerry Zaks' Broadway revival of the 1957 musical.

Hugh and Sutton took on the roles of Harold Hill and Marian Paroo in The Music Man, which ran from February 2022 to January 2023 at the Winter Garden Theatre in Manhattan.

'Sutton and Hugh's relationship is the reason Hugh and Deb [separated],' a source close to Foster told the outlet.

'A lot of people on Broadway knew, and we kept it quiet because both of them are so nice and great people. Everyone respected their privacy. But there was an affair and overlap. They are really happy now.'

They continued: 'Hugh's whole image is that he’s the nicest guy in Hollywood, so he doesn't know what to do with this.'

And while a source told DailyMail.com on October 26 that Furness 'had her suspicions when Hugh started working with Sutton' an industry source claimed the opposite to Us Weekly.

'Deborra-Lee was blindsided when she found out about the affair through the run of the show,' the insider said.

'It was apparently Broadway's worst-kept secret, and Deborra-Lee was the last to know. [Worse yet,] he didn't own up to it!'

The Force of Nature: The Dry 2 actress and Jackman's two adopted children - son Oscar Maximilian Jackman, 24; and daughter Ava Eliot Jackman, 19 - are legal adults, but they'll have a tough time dividing his alleged $180M fortune.

'For a woman who's been in a marriage for 27 years who then discovers her partner was unfaithful and isn't trustworthy, it's a pretty devastating life experience,' a friend of Deborrah-Lee's said.

'I think many people were shocked he could do this to her, especially as she's the mother of his children, and they've navigated three decades of life together. A little respect may have been in order.'

It's worth noting that the Deadpool & Wolverine action star fell in love with Furness while co-starring as a brain-damaged convict and a prison psychologist in ABC's 10-episode series Correlli in 1995.

Eyebrows raised yet again when the two-time Tony winner filed for uncontested divorce from her second husband Ted Griffin on October 22 in New York County Supreme Court - according to Page Six.

During their decade-long marriage, Sutton and the 53-year-old 9-1-1 producer-writer adopted seven-year-old daughter Emily Griffin, and she told Vogue in 2022 that her family 'spent Memorial Day' with Hugh's family.

It's unclear when the coy couple's alleged affair began, but it was In Touch Weekly that first reported on it December 13.

Foster divorced her first husband actor Christian Borle in 2009 after three years of marriage.

The Grammy nominee currently stars as Princess Winnifred in Lear deBessonet's Broadway musical revival of Once Upon a Mattress, which runs through November 30 at the Hudson Theatre in Manhattan.

Jackman - who's only an Oscar away from EGOT status - will next star in Craig Brewer's musical drama Song Sung Blue, Michael Sarnoski's drama The Death of Robin Hood, and Kyle Balda's comedy Three Bags Full: A Sheep Detective Movie.