Legendary rockers Led Zeppelin have been invited by the World Peace One organisation to reunite once more for a series of charity concerts across the globe. The Stairway To Heaven stars reformed in December (07) for a one-off tribute concert in London, but despite huge demand from fans for a full tour, the group have refrained from making any further plans. But the charity founder, Doug Ivanovich, hopes he will be able to convince the ageing band to return to the stage for another round of shows in the name of world peace. Other stars invited to play at the international events include Madonna, U2, Justin Timberlake and Velvet Revolver. The gigs are tentatively scheduled to kick off in May (08), with concerts in cities like London; Miami, Florida; Johannesburg, South Africa; and Beijing, China.