With 15 million record sales, Sarah Brightman’s two gigs at Athens’s open-air Lycabettus Theater on Friday and Saturday are sure to draw a big audience. The concerts mark the first stop in her Harem World Tour. The British singer, who has made an impact with her rich and elusive vocal prowess, makes an impressive stage appearance not just with her physical presence, but with her formidable vocal range as well. Brightman, who shot to fame through her appearances in the theater, is credited with a now-legendary appearance in «Phantom of the Opera,» a memorable duet with Placido Domingo in «Cats,» another duet, with Jose Carreras in 1996 for «Friends for Life» (which became the anthem for the Barcelona Olympics) and her successful partnership with Andrea Bocelli in the hit single «Con te Partito – Time to Say Goodbye,» a ballad heard the world over. For her tour, Brightman will be promoting her latest album, «Harem,» in which she explores the music of the Mediterrannean, the Middle East and the Orient, in collaboration with several folk artists, fusing traditional melodies with Western, pop-influenced tunes and adding a touch of operatic fervor to the world music mix. Fans of the diva will also be happy to hear older favorites, such as «Eden» and «La Luna.» Tickets for Sarah Brightman’s concerts on Friday and Saturday at the Lycabettus Theater are available from the Metropolis (64 Panepistimiou) and Virgin (7-9 Stadiou) record stores and the Hellenic Festival Box Office (39 Panepistimiou, tel 210.928.2000). Information at tel 210.600.2802.