Complex sentence: Towards the end of 2002 Kalsi worked with the teenage pop star Avril Lavigne, when she recorded a cover of Bob Dylan's "Knockin' on Heaven's Door" was sung by Lavigne at a War Child Charity Concert covered by MTV.
Split into simpler sentences: Towards the end of 2002 Kalsi worked with the teenage pop star Avril Lavigne. A cover of Bob Dylan's "Knockin' on Heaven's Door" was sung by Lavigne at a War Child Charity Concert covered by MTV.