Singer Jessie J is said to be upset that her friend, the Grammy winning Adele has not bothered to keep in touch with her ever since she tasted success.

The two talented singers were former students at the The BRIT School for Performing Arts and Technology.

"They used to be close. But now Jessie never hears from Adele, which she finds frustrating. It's almost as if she's too busy for their friendship since her phenomenal worldwide success," a source told the Daily Star newspaper, reports contactmusic.com.

They were close friends at the school, and Jessie has spoken fondly about their time "jamming" in the past.

Once earlier, Jessie had said: "I used to have jamming sessions with Adele between classes. We used to sing at lunchtime and someone would be playing guitar - it was fun."