Octavia Spencer has joined the cast of 'Instant Family'.

Octavia Spencer

Octavia Spencer

The Oscar nominee will star alongside Mark Wahlberg and Rose Byrne in the movie, which features a couple (Wahlberg and Byrne) who decided to foster some children but find themselves landed with three wild youngsters.

'Transformers: The Last Knight' star Isabela Moner will play one of the children, alongside Gustavo Quiroz and Julianna Gamiz.

According to The Hollywood Reporter, comedians Tig Notaro, Iliza Shlesinger and Tom Segura will round out the cast.

Mark will produce the movie alongside Steve Levinson and Sean Anders.

Anders, who previously directed Mark in 'Daddy's Home', will helm the movie from a script he wrote with John Morris.

The movie is set to begin shooting in March and will be released in 2019.

Meanwhile, Octavia recently praised her friend and 'The Help' co-star Jessica Chastain for working with her to receive a pay rise for an upcoming festive movie they shot together.

The 'Shape of Water' actress revealed how she opened her co-star's eyes to the inequality and challenges faced by women of colour, even compared to their white female counterparts.

While praising Chastain for her work to close the gender pay gap in Hollywood, she added: "Here's the thing - women of colour on that spectrum, we make far less than white women. If we're going to have that conversation about pay equity, we have to bring women of colour to the table. And I told her [Chastain] my story and we talked numbers and she was quiet and she had no idea that that's what it was like for women of colour..."

Octavia revealed how her co-star for the upcoming Christmas comedy took it beyond the conversation and made sure something was done about the payday.

She said: "I love that woman because she's walking the walk and actually talking the talk She said, 'Octavia, we're going to get you paid on this film.'

"She said, 'We're going to be tied together, we're going to make the same thing and you're going to make that amount.' And fast forward to last week, we're making five times what we asked for. And now I want what the men are making, I want to get there. But right now, it feels good to be in that conversation."