It's been a month since Demi Lovato un-followed former best friend Selena Gomez on Twitter and now the "Really Don't Care" singer is explaining why.

During an appearance on "Watch What Happens Live" Thursday, the 21-year-old "Camp Rock" actress agreed to play a game of Plead the Fifth, in which she was only allowed to skip one of the three questions asked

"You recently unfollowed your BFF Selena Gomez on Twitter. So much speculation about this," host Andy Cohen noted. "Can you tell us why?"

Lovato jokingly pleaded the fifth but then went on to reply, "I think it's just one of those things where people change and people grow apart."

In July, Lovato deleted Gomez on Twitter and then posted a picture of her swimming in the ocean, with a message that seemed to be directed at Gomez, writing, "Swimming away from the bulls--t bye bitch."

Whatever the reason was, neither star has issued a comment about their friendship. However, several reports suggested that Gomez's on-and-off again relationship with pop star Justin Bieber could have resulted in their friendship ending.

During the game Lovato was also asked to play a game of "Shag, Marry, Kill" - pitting her former fellow X Factor judge Simon Cowell, her ex-boyfriend Joe Jonas and Bieber against one another.

"I'd kill Bieber. I'd kill Simon. F--k, I'd kill Joe, too!" she said, adding "No, Joe and I are good friends, so I wouldn't kill him. I'd keep him around."

When guest Jessica Alba asked the singer "Who would you shag?" Lovato answered "None."

However, Lovato actually did plead the fifth when asked by Cohen "what was the most scandalous thing she ever saw a Disney Channel star do?"