Bobby Marks breaks down how much the Thunder should expect to pay in the luxury tax if Paul George decides to remain in Oklahoma City. (1:46)

Things will get expensive for OKC if George stays (1:46)

Paul George arrived in Oklahoma City early Saturday evening, as Russell Westbrook was hosting a private party in town late Saturday night as free agency opens, sources told ESPN.

Westbrook has organized the event, dubbed a "summer hype house party," being held at a property near Lake Arcadia. He invited around 500 guests with the promise of a "surprise performance by a multi-platinum artist."

Sources told ESPN that artist is Nas. The invitation says, "The FOMO will be real." Invited guests were required to sign a non-disclosure agreement.

The motivation behind the party is presently unknown, whether it's about free-agency recruitment, an announcement of something or just a summer house party -- but the timing is obviously intriguing.

As OKC general manager Sam Presti noted in his draft news conference, Thunder officials have been in communication with George and his representatives since the end of the season. And the dialogue is said to be positive.

George will be an unrestricted free agent at midnight ET after declining his player option on Thursday.

George also is strongly considering the Los Angeles Lakers, as well as the Philadelphia 76ers, but the Thunder and Lakers appear to have separated in a two-horse race.

The Thunder traded for George a year ago, shocking the NBA and embarking on a gamble of a 12-month recruitment with the hope of signing George to a long-term deal.