Fans of English heavy metal legends Iron Maiden will fill the Lokomotiv stadium in Bulgarian capital for the band's gig, with 25,000 tickets already sold.
Event organisers Sofia Music Enterprises said they expected 30,000 fans to attend the gig on June 4, but warned fans that the number of remaining tickets was limited.
The band will headline the company's annual Arena Music Festival as part of its tour to promote its latest album, A Matter of Life and Death, which reached Nr. 4 on the UK album charts.
The gig will feature a 30-tonne stage, built over two days by the band's 200-member technical crew.
The event is sponsored by Bulgarian brewery Kamenitsa and cellphone operator Vivatel and will feature several stands where fans will be able to buy the band's merchandising, including its latest album.
The band will be playing five songs from each of these albums plus other fan favourites and will be taking out a full on stage production, which will include the final appearances of Eddie's notorious tank.