Chris & Rihanna's Rockin' Romance

“We are very good friends,” Rihanna has coyly said of her rumored relationship with Chris Brown.

But as they say, actions speak louder than the words!

The “very good friends” got some very expensive jewelry for each other recently, OK! has learned.

Chris dropped more than $100K on two ruby-and diamond necklaces from Jason of Beverly Hills for his gal while his 20-year-old Grammy-winning lady reciprocated with a bling blingin’ cross.

“Rihanna gave specific instructions about Chris’ gift,” designer Jason Arasheben tells OK!. “She was very particular about wanting the cross to match his other jewelry.

As for Chris, 19, “He went for the heart theme,” Jason explains. “He said, ‘She’s going to love this because she loves hearts.’”