Faux Mantel Plan:

For the faux mantel you are going to need to remove the TV from the wall above the fireplace.

Home Depot sells pre-primed shiplap and you can cut it to the length you need.

Adhere the shiplap planks directly to the wall. You can adhere the planks with a finish nailer or  you can use construction adhesive- you will need to let this dry before mounting your TV back on the wall. 

You want the shiplap to go all the way to the ceiling starting flush with the top of the mantel. I would cut the boards the same width as the top of the mantel. Leave a cut out for your plug in and TV mount.

Frame out the shiplap above the mantel with 3" x 1" boards. Placing the board over the ends of the shiplap boards. Also add a piece of matching crown molding at the top. You can see the picture below. 

Paint all the shiplap. I recommend Alabaster White by Sherwin Williams. 

After it drys mount your TV back on the wall above the mantel. 

I did this process for the mantel in my living room with real shiplap.

In my bedroom I used faux shiplap if you like this option better. Here is a link to my faux fireplace in my bedroom if you would like to see more pictures: {Click HERE}