The US military will for the first time allow its members to wear uniform at a gay pride march.
The permission was granted for the Gay Pride Parade in San Diego, California, on Saturday, a military-wide Pentagon directive said.
The memo said the move was a one-off exception for this year's march only.
It comes after a longstanding ban on openly gay people serving in the US military - known as "don't ask, don't tell" - was ended last year.
"Based on our current knowledge of the event and current policies, we hereby are granting approval for service members in uniform to participate in this year's parade," Deputy Assistant Secretary of Defence Rene Bardorf said in the directive.
Permission was given on condition that military personnel take part in a personal capacity only and adhere to the US military's standards on uniform wear, she added.
Numerous service personnel marched at last year's San Diego event, but wore T-shirts bearing the name of their service branch instead of uniforms.
Dwayne Crenshaw, executive director of San Diego LGBT (Lesbian, Gay, Bisexual and Transgender) Pride, said he was delighted by the move.
"Today is a great day of pride! San Diego Pride is honoured to have the privilege of celebrating our country and our service members with dignity and respect," he said in a statement.
"The fight for equality is not over and it is not easy, but this is a giant leap in the right direction."
Under "don't ask, don't tell" (DADT), established in 1993, gay people could serve in the military only if they did not openly acknowledge their sexuality. Its abolition last September fulfilled a campaign pledge made in 2008 by President Barack Obama.