Frain has landed a guest role in the ninth episode, Entertainment Weekly reports.
He will play the owner of a pharmaceutical company who is determined to protect his organisation's secrets.
Frain played Franklin in True Blood and has also worked on shows such as The Cape, The Tudors and 24.
Gavin Rossdale, Matt Lauria, Lauren Stamile, Grant Show and WWE star The Big Show have also signed up for the fifth season of Burn Notice.
Burn Notice returns with new episodes on June 23 on USA.