This is the 1207th most frequent Russian word.
известный
Famous; well-known.
The word 'известный' is used to describe the actor as someone widely recognized or renowned.
Этот актёр очень известный.
This actor is very famous.
Here, 'известна' (feminine form of 'известный') describes Moscow as being noted or famed for its features.
Москва известна своими историческими достопримечательностями.
Moscow is known for its historical landmarks.
The word 'известным' here (masculine instrumental form) denotes his transition to a state of renown because of his accomplishments.