A MAN will face court today after he allegedly held up a McDonalds outlet with a knife yesterday before calmly sitting inside the restaurant with a coke.

It will be alleged the 28-year-old man walked into the fast food restaurant yesterday in Spearwood about 3pm armed with a 30cm fishing knife.

Police will allege he went up to the counter and demanded cash and a large coke.

After being given a sum of money and his coke the man sat down in the dining area with his beverage before police arrived.

The Busselton man was arrested at the scene and has been charged with armed robbery.

He will appear in the Fremantle Magistrates Court today.