Yes
Yes you can, we just completed a tile over brick project by following these steps:
Step 1: Protect Surrounding Surfaces
Place drop cloths over the hearth and the floor. Use painter’s tape to mask off adjoining walls and the mantel if it will remain in place.
Step 2: Clean and Prepare Existing Brick
If possible, you should remove the existing mantel for easier tile installation; it can be re-installed or a new mantel added later. Use a wire brush to remove any loose mortar or brick pieces from the brick surface. Soak a rag in white vinegar and scrub any soot from the face of the fireplace. Allow the brick to dry for up to two days before proceeding. Meanwhile, measure the fireplace to determine the number of tiles and quantities of thinset and grout that you will need.
Step 3: Create a Smooth Work Surface
Mix latex-modified thinset cement in a bucket according to the manufacturer’s instructions. Use a flat trowel to spread thinset over the brick, filling in the grout lines. Allow the thinset to cure. If the grout lines are still visible after the first coat has dried, apply a second coat of thinset to smooth out any dips or grooves. Allow the second coat to cure completely.
Step 4: Install a Ledger Board
A temporary ledger board will provide a useful guide for installing the tile in line with the existing fireplace opening. Align the top edge of a one-by-four board with the top of the fireplace opening and nail the board in place.
Good luck!!!