Lady GaGa performed John Lennon's iconic hit IMAGINE to rally support for a gay rights march through the streets of Washington, D.C. on Sunday (11Oct09).
The Poker Face star took to the stage at the Human Rights Campaign's official dinner the night before the protest, and put her own spin on Lennon's peace anthem with references to late student Matthew Shepard, a teen who died in 1998 after he was tortured for being gay.
And Gaga ensured she made an entrance with a very special support act - U.S. President Barack Obama.
The American leader addressed the dinner to tell the audience of his own plans to allow homosexuals into the U.S. military, and quipped, "I'm honoured to be opening for Lady Gaga tonight."
The singer also joined the march on Sunday, taking part in a street demonstration outside the White House.