Plans for the Grammys’ blowout 50th-anniversary show are back in full swing, now that the striking writers have agreed not to picket the Feb. 10 broadcast. We can tell you some of what those plans are. According to a well-placed source, the big ’surprise’ number will be a duet by Beyonce and Tina Turner, who has only rarely performed since 2000.

Recent sightings of Britney Spears at the Millennium Dance Studio in North Hollywood had led some fans to speculate that she might be rehearsing a big Grammys routine, à la her aborted ‘comeback’ at the VMAs in Las Vegas. When we followed up this rumor with our highly placed insider, the source told us: ‘Britney is banned from the building.’

A Grammys rep told us: ‘We haven’t released any presenters or performers, and until we do, nothing is confirmed.’ The Writers Guild has yet to grant the Grammys a formal waiver, although Recording Academy President Neil Portnow is on record as saying the ceremony would proceed as planned.