Selena Gomez' grandmother is ''very worried about her.''

The 21-year-old star - who sought treatment in rehab earlier this year for depression - was reportedly diagnosed with Lupus recently, and her family are urging her to take better care of herself.

Her paternal grandmother, Mary Gomez said: ''I am very worried about her. I pray to God every day for her - and all the people in our church are praying for her to get better.

''Selena is very stressed and concerned about her condition. I am, too.''

She added: ''She is too busy. She needs to rest. We all want her to get this under control.''

Selena has yet to comment on speculation she is battling the chronic condition, which causes the body's immune system to attack its own tissues and organs, but friends say she simply isn't ready to acknowledge it.

An insider said: ''She was so distraught and really freaked out when doctors told her there was no cure and she would have to live with it for the rest of her life. She's been on meds ever since.''

The brunette beauty's inner circle are also concerned about rumours she has rekindled her romance with her ex-boyfriend Justin Bieber, who she first started dating in 2010, again following his recent run-ins with the law.

A source told In Touch magazine: ''He's always had a spell over her and is such a bad influence and bad for her health.''