In a saucepan place egg, cover with water and bring to a boil. Boil for 8-10 minutes. Transfer to a cold water and allow to cool. Meanwhile prepare the rest of the salad.
Cut avocado into small cubes/chunks and place in a large bowl, add cherry tomatoes, chopped celery stalk, chopped red onion, chives.
Peel and chop the eggs.
Add chopped eggs to the salad, then add lemon juice, mayonnaise, salt and pepper. Stir until well combined.