On 29 January 1970 the band appeared on BBC's "Top of the Pops" again, performing "Witch's Promise". Evan rejoined the band in early 1970. He had stayed in London since the John Evan Band broke up, living with Anderson, and began studying music at the University of London. The pair did not see much of each other because of Jethro Tull's increasing workload, and Evan was reluctant to rejoin because of his studies, which gave him access to a free studio. He played as a session musician on the next album, "Benefit" (1970), following which Anderson said they needed somebody to play the keyboard parts on tour. His tutor eventually persuaded him that it was a good idea, and Evan formally joined. The album reached No. 4 in the UK and No. 11 in the US, and allowed the group to sell out 20,000-seat arenas, establishing themselves as a premier live act. In August, the band played to one of their largest audiences at the 1970 Isle of Wight festival.