Heat up oil in a big pot over medium high heat. Add celery, carrot, leeks, garlic and Italian mixed herbs. Keep stirring and cooking the vegetables for 5-7 minutes, season with pinches of salt along the way.
Once the size of vegetables is reduced by half, add water and cook the broth until it boils.
Add raw chicken breast and soaked lentils. Cook for 20 minutes.
At the last 5 minutes, remove chicken breast from the soup. Shred the chicken into pieces with forks.
Add drained cannellini beans and shredded chicken into the soup, cook for 2 minutes.
