Use stream of consciousness to answer the following. "I Ai n't Mad at Cha" is a song by rapper 2Pac released shortly after his death as the sixth single from his album All Eyez on Me. It was also his last single using the stage name 2Pac. The song features contemporary soul singer Danny Boy who provided the vocals for the song's hook. The song did well in the United Kingdom, reaching the number 13 on the UK Singles Chart and on the UK R&B Charts peaking at number 3. It was not released as a single in the United States, thus making it ineligible to chart on the Billboard singles charts (due to chart rules at the time), but reached numbers 18 and 58 in the R&B and Pop Airplay charts, respectively. It also reached number two on the New Zealand Singles Chart.

Answer this question based on the passage: who sings on i ain't mad at cha?
To answer the above question, the relevant sentence is: The song features contemporary soul singer Danny Boy who provided the vocals for the song's hook. Final answer: Danny Boy.