So it came as something of a surprise when she stepped out in a daring strapless black bodice top and tiny pink tulip skirt.
It seems her hardline training regime for Strictly Come Dancing may have already given her body confidence a massive boost.
Looking good: Former EastEnders star Natalie Cassidy heads to a wedding
The 26-year-old teamed her minuscule outfit with towering heels which matched the colour of her skirt.
Her accessories were kept to a minimum - simple diamond studs in her ears and a slim gold watch on her left wrist.
She also opted for a simple down 'do with her hair falling in loose curls over her shoulders.
Natalie was on her way to a wedding with boyfriend Adam Cottrell, 29, who was dressed more plainly in a grey suit and carrying what looked like an overnight bag.
It seems that the fitness regime of Strictly Come Dancing is doing Natalie the world of good.
She has been looking fresh-faced and slimmer than usual in recent weeks as she trains for the show, which starts on Friday, September 18.
However, she has also had to contend with rumours of a Strictly romance with dancer Vincent Simone, her partner on the show.
The pair were spotted in what appeared to be an intimate embrace in the street during a break from rehearsals.
But Natalie, who made her name playing Sonia Jackson in EastEnders, has downplayed any suggestion of a new relationship.
Loved up: Natalie strolls down the street with boyfriend Adam Cottrell
The actress has probably become more famous for her yo-yo dieting than her roles.
In 2007, she showed off a spectacularly slimline figure, plunging from a size 14 to a size 8 and losing four stone in less than six months.
Natalie launched a fitness DVD on the back of her weight loss which became one of the fastest-selling fitness DVDs ever.
However, she soon piled on the pounds and admitted she had been deeply unhappy while thin.
'I’ve had a lot of issues with my body over the years,’ she said last month.
‘I’ve struggled with my weight and I’ve struggled with diets – I’ve tried every one in the book, from the cabbage soup diet to Atkins and even one where I could only eat one mushroom every four hours.
'None of them ever worked and none of them ever made me feel any better about myself.’
She said meeting Adam earlier this year had given her a huge confidence boost and it was this that led her to go on Strictly.
'I just want to learn to dance. If I happen to lose some weight at the same time then that will be a good thing but it’s not why I’m on the show,' she said.
'Neither is it for the money or to raise my profile.'
Gizza kiss: Vincent Simone and Natalie Cassidy are caught in what looks like a compromising position after practice
