The 36-year-old took to Instagram this week for a selfie session, revealing her extremely slim figure in a white crop top.
F1 driver Lewis, 30, and former Pussycat Doll Nicole started dating in 2007, but their relationship has been very on and off.
But according to sources this split is the final nail in the coffin for Nicole, after it was reported Lewis refused to marry her.
An insider told the Mirror: “The split has been devastating for Nicole. She feels the only way she can move on is by putting distance between her and Lewis.
“While their split was amicable, she and those around her feel it’s not healthy for them to remain friends.”
It was recently claimed that Nicole was upset with pictures of Lewis partying with other women so soon after their break up.
A source told new! magazine: “Nicole has been in pieces about the split. Lewis promised her he’d respect her and not go rushing into another relationship or even hang out with other girls.
“So she was devastated when she saw him partying in New York. She’s been in floods of tears most of the time.”