Despite owning competing record labels, distributed by competing majors, Dr. Dre and Jay Z have been most amicable for more than 15 years. More than once, the pair has done business together, from Jay’s writing of Dre’s “Still D.R.E.” hit single verses, to Dre supplying sounds on Jay’s Kingdom Come, and rapping on Vol. 3: Life and Times of S. Carter, and reported 2010 Detox single “Under Pressure.”

With both artist-turned-moguls playing near (perhaps above) the billionaire mark, the friends will now square off in the digital streaming music space. Business Insider reports that Jay Z (through his Project Panther Bidco) is securing a $56 million purchase of WiMP. The company, who also produces the Tidal platform, is one of Spotify’s biggest rivals, especially popular in Western Europe and Scandinavian countries.

Reuters reports that WiMP’s largest share-holder has already accepted Project Panther’s offer, presumably completing the transaction.

Across the country, Dr. Dre’s mega-millions stake in Beats Music (now owned by Apple) has led the electronics maker into the streaming space, with strong involvement from Dre and former Interscope Records Chairman Jimmy Iovine.

As an anecdotal aside, Dr. Dre’s classic 1992 solo debut, The Chronic, is presently not available on Spotify or Beats Music.

If the fight for exclusivity surrounding music on streaming platforms grows, who do you think can win the lion’s share?

Related: “THE FORBES LIST JUST CHANGED.” Dr. Dre Speaks on Becoming the First Billionaire in Hip-Hop (Video)