SL Green and Caesars Entertainment have a glam new partner in their hoped-for Times Square casino — Brooklyn-born billionaire rapper and entertainment impresario Jay-Z and his Roc Nation, Realty Check has learned.

The three-way partnership, to be announced at SL Green’s annual investor conference on Monday, marks a dramatic twist in the developer’s and Caesars’ quest to launch a casino at SL Green’s 1515 Broadway office tower. (They’re among a half-dozen teams that are also expected to submit proposals to the state for a first full-scale casino in the Big Apple.)

Although details have yet to be spelled out, Jay-Z and his team are expected to oversee entertainment programming at 1515 Broadway and at other SL Green properties at the “Crossroads of the World.” The city’s largest commercial landlord, SLG has interests in six Times Square properties with a total of more than four million square feet.