The Hackney-raised rapper dropped by Radio 1 on Tuesday (18 June) to speak to DJ Sara Cox and while there he revealed that Millie had got fed up with pressures from the Made In Chelsea producers.
When asked whether Millie was still in the BAFTA award-winning show, Pro Green said: "No. She'd had enough of it. They were just trying to push her... I'm happy with her to do anything that makes her happy, and it really wasn't making her happy because she was getting pressured to film things that she just wouldn't film."
The Quality Street heiress has been a regular face on Made In Chelsea since the first series and has enjoyed a number of memorable story lines, including a romance with former cast member Hugo Taylor, a huge fall out with best friend Rosie Fortescue and smacking ladies' man Spencer Matthews across the face after finding out that he'd cheated on Louise Thompson.
However, now that she has settled down with her rapper beau, she has taken a bit of a back seat from the show and she was only seen a handful of times in the latest series.
And Pro Green - who proposed to Millie in Paris in March - explained that this is because she has decided to keep her private life away from the cameras.
He added: "She wanted to keep her private life private and that doesn't fit very well with the format of the show when everyone in it's acting like a wally and are trying to play up to it just for the story lines. Everything changed for her."
Rumours that 23-year-old Millie was leaving Made In Chelsea emerged earlier this year, as it was believed that she wanted to accompany her soon-to-be-husband to America in 2014 when he goes on tour.
And now she also appears to have confirmed the news of her departure on her Twitter account, by re-tweeting a fan on Wednesday (19 June) who said that she was "gutted" that Millie wouldn't be on the show anymore.
The fan wrote: "@millsmackintosh gutted you're leaving MIC!!!! You're the voice of reason! #smackintoshforlife"
We're gutted too!
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