Performing at "Capitol Fourth" on the National Mall, Diamond and Manilow were accompanied by the National Symphony Orchestra that performed several songs from the "Lincoln" soundtrack.
At one point Diamond sang "Sweet Caroline" as tribute to the Boston Marathon bombing victims and survivors. Manilow closed the concert with a rendition of "Let Freedom Ring" before the audience headed to the Capitol's west lawn to see the 17-minute display of fireworks.
For photos of the Fourth of July celebration across the country click here.
Notable deaths of 2014 [PHOTOS]