Dale Earnhardt Jr., doesn't seem like a guy who is easily surprised or tricked.

Leave it up to his mom, Brenda, to pull a fast one on him.

In a recent taping for ESPN, Earnhardt Jr. penned a heartwarming letter to his mom for Mother's Day, not knowing that Brenda was listening in the other room.

After he finished, she came in to join him, and the two enjoyed a sweet moment.

Here is what Junior wrote in his letter to Brenda, who was married to Dale Earnhardt Sr., from 1972-79.

Dear Brenda,

I thank God everyday that you and Dad brought my sister (Kelley) and me in to this world. But I think back to the six-year-old kid. You a single mother, us losing everything in a house fire. You gave custody of us two kids to our father, knowing that he could provide a promising future.

I remember your 12-hour round trips for your summer visit. I remember your Norfolk apartment floor covered in presents each Christmas.

I'm thankful that we are together today, as I am now older and wiser to appreciate the sacrifices you made for us. You never failed at making us feel loved.

I love you.

Happy Mother's Day, Mom.