My best friend and I like the same guy!

Only found out that my my best friend likes this guy in our friendship group. I like him too and she knows this. However she has told her other friends that she likes him and was one of the last people to find out.

From the sounds of it he likes her also, we all hang out together how am I going to handle the fact that my bestfriend is going to be dating the same person I like??

Any advice would be great!