Chris Martin and Bono performed on piano together to help raise money for charity.
The Coldplay singer and U2 frontman performed 'Perfect Day' and 'Beautiful Day' before the Parlor grand piano sold at auction for $1.9m (€1.4m) at a fundraiser for The Global Fund to Fight Aids in Africa.
The pair sang together at Sotheby's in New York in front of a star-studded audience at The (Red) Auction celebrating design and innovation.
It was curated by Sir Jonathan Ive and Marc Newson in collaboration with Bono.
The 'Walk On' hitmaker and activist said: "Jony and Marc are the Beatles and Stones of the design world.
"The money raised is a lifeline, literally, for so many people, but nights like this also serve as a reminder of the historical opportunity we have to end AIDS."
The 53-year-old famously labelled Chris a "w*****" live on Jo Whiley's Radio One show back in 2009.
He insulted the singer after the presenter asked what he thought of the star, to which he replied: "I think he's that good a melodist, but he's a w*****."
The musicians have now ended their feud and are rumoured to be collaborating together on new material.
Their performance inspired more than a dozen bidders to compete for the piano, which was finally won by philanthropist Stewart Rahr for $1.9m (€1.4m).
A Zero Generation Bono 'signature' guitar was also sold for $250,000 (€184,000) and the event was attended by Nile Rodgers, Chic and Courtney Love, among others.
They helped to raise $26m (€19m) overall for the charity, which also helps battle tuberculosis and malaria in Africa.