Matthew McConaughey's wife Camila Alves has given some very rare insight into her 'tricky' relationship with her mother-in-law Mary Kathlene 'Kay' McCabe - laying bare the toxic behavior that she used to endure at the hands of the actor's mom.

The Brazilian model, 41, shared about the rocky beginnings with Kay, who the family have nicknamed 'Ma Mac', on a new episode of Southern Living's Biscuits & Jam podcast.

Alves, who shares three kids with the Oscar winner, 53, to whom she's been married since 2012, revealed that after she first began dating him in 2006, Kay, now 91, started 'testing' her.

'She did all these things when I first came in the picture, right? She was really testing me. I mean, really testing me,' she recalled.

'She would call me by all of Matthew's ex-girlfriends' names, she would start speaking Spanish with me in a very broken way, kind of putting [me] down a bit. I mean, all kinds of stuff.'

'Tricky': Matthew McConaughey's wife Camila Alves, 41, gave a rare insight into her 'tricky' relationship with her mother-in-law Mary Kathlene 'Kay' McCabe, 91 (seen together in 2020)

Alves, who shares three kids with the Oscar winner, 53, to whom she's been married since 2012, revealed that after she first began dating him in 2006, Kay, now 91, started 'testing' her

Tough beginnings: 'She did all these things when I first came in the picture. She was really testing me. I mean, really testing me,' Camilla revealed on Tuesday; The trio seen in 2014

Camila then described the incident that got Kay to finally accept her as part of the family.

She recalled how after she landed a modeling job in Istanbul, and got an extra first class ticket and a free stay at a hotel, she told her mother-in-law: 'Ma Mac, you're gonna come with me.'

'The whole way there, the whole plane ride to Istanbul, she was telling me all these stories and putting all these things in my head,' Camila went on.

'When we landed, I was like, "Okay, all right. Let me buckle up. Let me get ready for this situation."'

'About day three, I was taking her to her room, and she got into this whole other thing that it's not my place to share, and she starts crying, and I'm like, "Oh my gosh!" You know, "Ma Mac!" and feeling so sorry. And as I put her to bed, I look at her and I'm like, "Oh my gosh. She's full of s**t.'"

That's when Camila decided that it was time to stand up for herself.

'So I just [flipped] it on her and brought my spicy Brazilian, Latin side, and I let her have it. So I went back at her, and we had it back and forth, back and forth.'

At the end, the interaction earned her Ma Mac's respect.

MIL: 'She would call me by all of [his] ex-girlfriends' names, she would start speaking Spanish with me in a very broken way, kind of putting [me] down a bit,' she shared; Pictured in 2014

All good: Camila said her relationship with Kay turned a corner after she finally stood up for herself one day: 'She just looked at me and she was like, "Okay. Now you're in"'; Pictured 2019

'She just looked at me and she was like, "Okay. Now you're in,"' Camila explained, adding, 'All she wanted was for me to fight back.'

She revealed that ever since that day the duo have had a great relationship, though it can get 'tricky' at times.

'From that day on, that night on, we have the most amazing relationship, and I have so much respect for her.'

'She has so much respect for me,' she shared, adding, 'it can get tricky sometimes.' However, Camilla explained, 'We always end with a good laugh and a joke.'

And in 2020, the pair discussed having a close bond and how 'it took some work' to get to the place they are today on The Drew Barrymore Show.

Kay said that at the beginning of Camila and Matthew's courtship, the two strong-willed women were 'testing each other' but the model saw things a bit differently: 'Well I'll say more you were testing me,' she said.

Camilla is not the only one in the family who's had a tough time getting along with Ma Mac at some point.

Matthew famously didn't speak to his mother for eight years after she continually leaked their private conversations to the press, prompting him to eventually set 'some boundaries' with her.

'I would have conversations and then all of a sudden—whoop—what we’d talk about would end up in the paper three days later,' the Dallas Buyers Club star shared on The Howard Stern Show in 2020.

Happy family: Alves started dating McConaughey in 2006 and they tied the knot in 2012. The couple share three children together, Levi, 15, Vida, 13, and Livingston, 10; Seen in 2019

Candid: In 2020 Matthew and his mother Kay sat down for their first joint-interview, after the release of his memoir, which details their eight-year estrangement

After continuously explaining their chats needed to be kept between themselves, he reached his tipping point after she gave a televised tour of his childhood home.

When Stern asked if he stopped talking to his mother after she showed off the bed where 'he lost his virginity,' he explained those years were 'tough.'

He also detailed their eight-year estrangement in his 2020 memoir, Greenlights.

Over the years, Matthew has 'forgiven her' and she even quarantined with him, Camila and their children, Levi, 15, Vida, 13, and Livingston, 10, during the Covid pandemic lockdowns in 2020.

'It was tough for eight years, but we went through it and we're on the other side of it. It's good,' he shared, noting things between them are no longer 'strenuous.'