"She actually sent me a song a while ago and she wanted me to be a part of it," Rihanna revealed. "And I was like, 'Hell yeah, of course, that's my girl,' and the song is amazing. So we'll be recording that together pretty soon."
And if Rihanna's description of her good friend is any indication, it's probably safe to say the planned tune will be anything but downbeat.
"When I first met her, her personality was so on point," she said. "I felt like she had no edit button, she was really fun and had a great sense of humor."
As for not being able to fly over to India for Katy's nuptials last month because of obligations related to her new album (due Nov. 16), Rihanna admits it's definitely not something she's happy about.
"I am crushed that I missed that wedding," she said. "I will never, ever forgive myself for that."