Bruno Mars
Bernadette Hernandez, Bruno Mars (PICTURED) mother, has died of an unexpected brain aneurysm.

Bruno Mars is in mourning following the unexpected death of his mother.

Bernadette Hernandez was rushed to Queens Medical Center in Honolulu, Hawaii after suffering a heart attack on May 31.

The mother-of-five is believed to have passed away from a subsequent brain aneurysm on June 1. She was aged 55.

Rihanna led the celebrity tributes in the wake of her death.

"Sending my love and condolences to @BrunoMars at this difficult time! I'm sincerely praying for you bro! #1Love"she wrote on twitter.

Stars including former American idol judge Randy Jackson and actress Jennifer Love Hewitt also paid their respects and expressed their condolences online.

"Terrible news. Praying for you @brunomars" tweeted Jackson.

Love Hewitt said: "My heart is breaking for Bruno Mars and his family tonight. I know all too well, to recent and too deep what they are prayers."

Hernandez's condition was first reported by Star magazine, who said the Philippines-born matriarch was in critical condition after suffering a sudden heart attack.

"Bernadette is in hospital and the grandkids are all here, I'm looking after them," family friend Anita Sojot told the magazine.

"The family is on it's way here right now and we are going to discuss what to do next."

Hernandez is survived by her Grammy-winning son, his brother Eric and their four sisters Presley, Tahiti, Tiara and Jamie.

Bruno known for hits including Just the Way You Are and Grenade is yet to comment on his mother's death