The Love Actually star has lost more than a stone on the Cambridge Weight Plan diet, while also struggling with Lyme disease and ME.
In an interview with Hello! magazine, Martine has opened up about how her body confidence has changed since her weight loss, saying it now feels more 'genuine'.
'Before I lost the weight I'd switch the confidence on when I needed to. In the industry I've grown up in, you're so scrutinised, it's what you do; you put on your face and go out there, even if inside you don't feel at all good about yourself', she told the publication.
'Now, that confidence feels more genuine. I set myself a goal and I've achieved it and, while a stone might not sound like a lot to some people, on my frame it has made a huge difference, not just to how I look but how I feel about myself.'
Martine also discussed how she managed to achieve her incredible weight loss goals, saying she avoided doing anything 'drastic' as she wanted to feel fit and strong after her previous health battles.
'Because I've spent so long fighting to feel healthy again, I didn't want to do anything too drastic that was going to make me feel lousy, but after having Rafferty I found it so tough to lose my baby weight and that does start to affect your self-esteem.
'I'd tried the Cambridge Weight Plan before and had great results. I needed something that would work swiftly because I think you can lose the will if you're not seeing results quickly enough. But it's rigid enough for me not to stray.'
The former Eastenders actress also said that becoming a mum put everything in perspective, including her weight worries.
'I give thanks every single day that motherhood is something I've been blessed to experience. It sounds like such a cliché but having Rafferty really did put everything into perspective.
'All those things I'd worried about all my life – the career, the weight; all seemed trivial in comparison to this little person we had created. Once I'd got that perspective, the rest seemed to fall into place.'
The mum-of-one has previously been very open about the body image pressures of growing up in the public eye.
'People spoke about me like I was a piece of meat and I can't believe that's still going on in this day and age,' she told The Mirror.
'I'm sure people still say horrible things now, but it's water off a duck's back because I have an anchor within myself. But it's so dangerous when you are younger.'
Despite brushing off the comments in recent years, Martine also admitted that it hasn't always been that way, and during her teenage and young adult life she felt huge pressure to fit into sample sizes and to look good on camera.
'Growing up in the public eye, you are judged by everybody and you work hard to try to keep everyone happy… I was always conscious of staying as thin as I could be,' she said before continuing, 'It looked better on camera, meant I could fit into size 8 samples sizes, and it was easier and more affordable with stylists.'