Having often guested on each others' tracks, Jay-Z and Kanye West teamed up last year to release Watch the Throne, a chart-topping album that's spawned some wildly successful singles (Otis, Niggas in Paris), and graced the upper end of many a critics' end-of-year poll.
This week sees the pair descend on London for a string of Watch the Throne shows at the O2 arena. To mark the occasion, for this week's readers panel we'd like to hear your thoughts on which of them is ultimate rap star.
Is it the multi-million-selling, Roc-A-Fella-founding, Beyoncé Knowles-marrying Jay-Z?
Or is it the multi-million-selling, Taylor Swift-bothering, opinion-dividing upstart Kanye West?
If you'd like to take part in this week's panel, send us a paragraph of no more than 200 words on either Jay-Z or Kanye, making your case for who is best. Send it to adam.boult@guardian.co.uk before 9am this Friday 18 May, with the subject line J/K.