Washington  - Presidential candidates Barack Obama and John McCain will make their first joint appearance of the 2008 election next month at a mega-church in California, the church announced Monday.

Presumptive Democratic nominee Obama and his Republican rival McCain have agreed to attend a religious forum at the 22,000-member Saddleback Church in Orange County on August 16, in what is likely to be the only meeting of the two White House hopefuls before the parties hold their nominating conventions later in the month.

But the appearance is not being billed as a debate. Each candidate will be interviewed separately by the church's founding pastor, Rick Warren.

Warren, a leading voice of the Protestant evangelical community in the United States, said the forum would be focussed on the candidates' leadership abilities and principles rather than specific policy proposals.

McCain had been pushing for the two White House hopefuls to hold a series of weekly townhall meetings before the party conventions, but the proposal fell through amid bickering between the two campaigns.

Obama and McCain will be holding three traditional presidential debates before the November 4 election. (dpa)