Nick Jonas and Kate Hudson are reportedly keeping their rumored romance very casual. Even though the 36-year-old “Bride Wars” actress and 23-year-old singer have been spotted spending quite a bit of time together lately, sources revealed that their romance is simply a "fling." 

"It's definitely not anything serious," a source told People. "They were both single and seeing other people too. Kate's mostly focusing on her boys and doesn't want a serious relationship right now." 

According to the New York Daily News, sources told Us Weekly that things are so casual between Jonas and Hudson that she doesn't want to introduce the "Jealous" singer to her sons, Ryder, 11 and Bingham, 4. The magazine also reported that Jonas was the one who initiated the romance by asking Hudson out on a date after having a crush on her. 

As previously reported, the "Scream Queens" actor isn't ready to dish on his dating life, telling 94.7 Fresh FM in a recent interview that he wanted to keep "some things to [himself]." 

"It's a strange place where a little thing can turn into a lot," Jonas explained. "But it’s about how much of that you kind of want in your world and just living your life and knowing that people will have their opinion.”

Jonas, who split from Miss USA 2012 winner Olivia Culpo in June, was also rumored to have dated Kendall Jenner. Hudson, meanwhile, has been linked to "Dancing With the Stars" pro Derek Hough following her December 2014 split from Matt Bellamy.