Jay-Z joined by onstage by Chris and Gwynnie at London show

Jay-Z was joined onstage tonight (September 27) by special guests Chris Martin and Gwyneth Paltrow on vocals as he played the second of his two London shows this week.

The surprise came at what was the first ever hip-hop gig at the prestigous Royal Albert Hall.

Performing in front of a sold-out crowd, as he did at Wembley Arena in the UK capital at the weekend (September 24), the rapper brought out the Coldplay singer for 'Dead Presidents II' and 'Heart Of The City (Ain't No Love)' from Jay-Z's classic LP, 'The Blueprint'.

Martin's Oscar-winning actress wife Paltrow supplied backing vocals on a few tracks including 'Song Cry', also from 'The Blueprint'.

Paltrow had previously sang in the 2000 movie 'Duets', and has appeared onstage with pal Sheryl Crow in the past. She has also had a couple of hits in Australia.

Nas also joined his old sparring partner onstage, as he did at Wembley (September 24), to sing three songs - 'Hate Me Now', 'Made You Look' and 'If I Ruled The World'.

Beyonce also appeared again, performing 'Crazy In Love' and 'Deja Vu'.

The rapper, who has now completed his UK tour, is releasing his new album 'Kingdom Come' - confirming that he has reversed his decision to retire - in November 27.