U2 frontman Bono sang the band's hit 'One' at the funeral of Dave Goldberg on Tuesday.
According to the New York Times, he sang 'to a simple accompaniment' and ended in silence.
Bono was just one famous face among many at the funeral of Mr Goldberg, who had been chief executive of SurveyMokey.
An estimated 1,700 people attended, including Hollywood actor Ben Affleck, Facebook founder Mark Zuckerberg, and Star Wars creator George Lucas.
Mr Goldberg, the husband of Facebook COO Sheryl Sandberg, died on Friday from head injuries after he collapsed on a treadmill at a villa in Mexico.
Among the tributes to him was a post from President Obama's office to the White House's official Facebook which said, Mr Goldberg “embodied the definition of a real leader.”
Ms Sandberg had also posted a tribute to her own Facebook account.
She thanked the couple's friends and family "for the outpouring of love over the past few days", describing it as "extraordinary".
Her poignant tribute - which was 'liked' immediately by Facebook founder and CEO Mark Zuckerberg - recalled how the pair met and how businessman Dave "introduced" her to the internet for the first time.
In the post, she wrote, "If the day I walked down that aisle with Dave someone had told me that this would happen – that he would be taken from us all in just 11 years – I would still have walked down that aisle.
"Because 11 years of being Dave Goldberg’s wife, and 10 years of being a parent with him is perhaps more luck and more happiness than I could have ever imagined. I am grateful for every minute we had."