Marisa Ramirez, who plays Maria Baez on CBS' Blue Bloods, just got upgraded to a feature role in the show's November 22 episode "Bad Blood." Oz star Kirk Acevedo will be introduced as Baez's ex-drug addict brother. Just so happens he's suspected of murder in a case Baez and her senior partner Danny [Donnie Wahlberg] have to solve.

According to Ramirez, introducing Baez's estranged relative will give new insight into her character.

"You finally get to learn a little bit of the backstory of Maria," Ramirez told Zap2it, "at least between her and her brother. You also find out why she became a cop ... it had to do with him.

Now on to her fourth episode, Ramirez had no idea how many of Danny's partners had come in gone in earlier seasons. Having not watched the show, she had no idea the show had already been through two other partners which included Jennifer Esposito as Detective Curatola and Megan Boone who now works on The Blacklist.

Not knowing Baez could be a reoccurring role on the show, Ramirez is blown away that she's lasted this long.

"...just the fact that I was offered one episode in February and now here I am, having relocated and started a new life on the East Coast. It's crazy, but it's such a blessing. And to be able to find different pieces of my character and have them start to develop, it's a lot of fun."

Blue Bloods airs at 9 PM on CBS.