Verbal agreements and written discussion with the promise of signing a contract with a music artist

An unknown music artist is discovered on a social network by Mr X. The unknown artist and Mr. X have verbal and written discussion about the unknown artist music career. Mr. X and the unknown music artist verbally agree that a contract will be signed and Mr. X will receive payment for his services. Mr. X flies the unknown music artist to him and introduces the unknown music artist to a third party that will also assist the unknown music artist. The contract is not signed but the unknown music artist promises to sign it. The unknown music artist music career has taken off and now the unknown music artist feels that the third party should pay Mr. X and the third party feels that the unknown music artist should pay Mr. X for his services. The unknown music artist gives a interview where the unknown music artist states that there music career by being discovered by Mr. X What are the legal steps Mr. X needs to take to receive payment that he and the unknown music artist verbally a