I first spray painted the inside of the fireplace with a black high heat spray paint from Home Depot. I then filled the front crack on the fireplace - can't remember what product I used, but Google should suggest some or someone at Home Depot. :)
Next, after taping, I used a 3/4" thick roller to apply an acrylic primer recommended by Hirshfield's.
As the brick sticks out quite a bit, I then had to take a paint brush and fill in the lines which was very tedious. I did two coats of primer, as it soaked into the brick and let each coat dry 24 hours in between.
After the primer, I painted one coat of matte paint to give it a flat finish. The white matte color I chose was almost exactly the same as the primer, so I would suggest skipping another can of white paint to save money and just doing the primer first to see if you are satisfied. I still have some touch up work to do, but all in all, I'm very happy with how it turned out. It definitely adds a cozy, modern feel to our home and compliments the woodwork around it.