The "Umbrella" singer is concerned by troubled Amy's recent behavior and hopes she can overcome her drink and drugs demons and get her career back on track.
Speaking at the MOBO Awards nominations party at London's Movida nightclub on Wednesday night (08.22.07), Rihanna said: "I think she is an amazing artist."
"She's definitely one of my favorite singers in the UK, and I wish her well."
Rihanna - who was nominated for two awards, while Amy, who checked out of rehab for a second time last week, received an impressive four MOBO nods - has made no secret of her admiration for the "Rehab" singer in the past.
She said: "I love her. She's so real. She's like, 'This is who I am - whatever.'"
Amy, 23, has canceled her European tour and postponed all her US concerts after overdosing on a cocktail of drugs earlier this month.
She was being treated for suspected alcohol and drug abuse at Essex's Causeway rehab clinic, along with husband Blake Fielder-Civil.
However, the couple quit on Sunday night (08.19.07) following a series of heated rows.