Yes, you can!
You can use the subject pronouns (yo, tú, él, nosotros, vosotros, ellos) followed by "mismo/-a/-os/-as meaning "myself", "yourself", etc.
Mismo will have to agree with gender and number though, in this case:
"Voy a decírselo yo mismo" (I am going to tell him myself--> if speaker is a man)
"Voy a decírselo yo misma" (I am going to tell him myself--> if speaker is a woman)
"Vamos a decírselo nosotros mismos" (We are going to tell him ourselves)--> if the speakers are masculine plural)
Noted for a new lesson soon.