Rihanna is reportedly "cool" with Chris Brown's relationship with model Karrueche Tran.

Related: Chris Brown's dinner date with ex

But the 24-year-old 'Diamonds' singer is reportedly throwing a $100,000 Halloween party tonight (31.10.12) and is concerned the 23-year-old 'Turn Up The Music' singer will bring along his ex-girlfriend who he has been in constant contact with since he dumped her because of his "friendship" with Rihanna.

A source told HollywoodLife.com: "Even though Ri cool with what's going on [between the three of them] I ain't sure if she trying to have KT all up in her party.

"And KT don't want to go. Ri's crew don't like her. KT should stay at home."

Rihanna has reportedly invited more than 300 guests to her party tonight and is paying for an open bar.

Friends close to Chris recently revealed he is very confused about his feelings for his ex-girlfriend and they often exchange flirty messages.

A source said: "She basically lived at his house when they were together and she still feel some type of way about the entire situation. She's trying to be over him, but he [keeps] texting and sending her pictures of them together and [telling] her he [misses] her all the time and this and that. I wish he would be with her if he feels that way but I know he's a dog but Karrueche doesn't think so."

Friends of Karrueche, 22, insist Chris is chasing her and not the other way around.

The insider added: "I love Karrueche, that's my girl and she's not all in Chris' face trying to push up on it. She's keeping it real classy and cute, and he's been chasing her."

The former couple had dinner together at Wokcano in West Hollywood on Friday (26.10.12) before attending the opening of new store Wild Style.