U.S. President Barack Obama, former President Bill Clinton and 2016 presidential hopeful Hillary Clinton were among the top politicians who attended the service at the St. Anthony of Padua Church in Wilmington, Delaware in memory of the state's former attorney general, who died last month, aged 46, following a battle with brain cancer.

Visibly grief-stricken Joe Biden did not speak at his son's funeral, but President Obama read an emotional eulogy and Martin performed Coldplay's 2005 song 'Til Kingdom Come.

The British rocker reportedly volunteered to sing after discovering that Beau was a fan of the band.