As well as recently releasing a Greatest Hits album with the pop group, Pinnock is also making her acting debut in the forthcoming romcom, Boxing Day.
The film was written and directed by I May Destroy You star Ameen, who produced the movie and plays the lead role as Melvin, a British author living in the US.
Pinnock plays Melvin’s ex, a famous singer who confronts him when he returns to London with his new fiancée, Lisa (Aja Naomi King) at Christmas.
Ameen, who appeared alongside Pinnock on GMB, said Pinnock was “one of the most dedicated new actors” he’d ever met, in a new interview on Good Morning Britain.
Admitting he’d been less aware of Little Mix before casting Pinnock in his film, Ameen said he’d been captivated by “how honest she is” after seeing an interview with her.
“You’re talking about someone who’d go do her work, do the whole pop star thing then come back at 8pm... and really study acting,” he said.
Ameen was previously best known for his role as Simon in Michaela Coel’s critically adored BBC series, I May Destroy You.
During the interview, Pinnock also offered some frank insights into her struggles as a new mother, after giving birth to twins in August.
“I don’t know how I’m functioning – I don’t know how I do it,” she admitted, as she praised her two sisters for helping out.
“Both of my sisters have honestly been incredible. I’ve got so much help around me,” she continued.
Earlier in November, she revealed that she would not be disclosing the gender of her children, or what names she and fiancé Andre Gray have given them.
“I’m just gonna keep it to myself,” she told The Telegraph.
Boxing Day is released on Friday 3 December.