speak of the devil (verb)

1. As soon as my friend mentioned watching a movie, speak of the devil, the film director herself appeared.

2. While discussing redesigning my living room, speak of the devil, the famous architect I admired walked into the room.

3. I was just talking about my favorite fashion designer when, speak of the devil, I saw her walking down the runway.

4. We were discussing the scariest movies we had ever seen and, speak of the devil, the actor from a terrifying horror film showed up at our table.