Shall I go out with my crush's best mate?

I have a “friend” who says “we are just friends” I really like him & he gives mixed signals. He is back in India until Feb. His “best mate” has been texting me & asked me to hangout & catch a movie. Shall I mention it to my “friend” as during recent talk with him, he wondered why I was still talking to his “best mate” while he himself is out of the country. Shall I mention it & go or shall I not go at all?