In a string of casting news, "The Secret Life of the American Teenager" star Ken Baumann has been tapped to have a recurring role on ABC's "Castle" while "Heroes" star Masi Oka is coming to "Hawaii Five-0" as a guest star.

Baumann, known for his role as Ben on the ABC Family series, will be the first boyfriend of Molly Quinn's Alexis Castle. In his first episode, "Punked," Richard Castle is dealing with the fact Alexis is excited about having her first boyfriend, but he's unnerved that she's not confiding in him with all the details. "Castle" returns with the new season Monday, September 20.

Meanwhile, Oka is becoming part of Steve McGarrett's team as the coroner. According to TV Guide, his character will appear in the fourth episode but there is a possibility that he would come back for future episodes. "Hawaii Five-0" debuts Monday, September 20 as well.