Two gay groups will march in South Boston's St. Patrick's Day parade, the nation's second largest behind New York.

LGBT rights group Boston Pride and gay veterans organization OutVets are the first two groups to participate in the annual Irish-American march.

The Allied War Veterans Council, which organizes the parade, had imposed a longtime ban on LGBT groups, saying that homosexuality conflicted with Catholic doctrine. In 1995, the Supreme Court upheld the group's right to exclude gays.

Malcolm Carey of Boston Pride applauded the move.

“This is a huge step forward in our mission to have inclusivity in our city and in the Boston-area community,” he told Reuters.

Mayor Marty Walsh, who skipped last year's parade due to the ban, will march in Sunday's parade.

“With this year's parade, Boston is putting years of controversy behind us,” Walsh said in a statement.