Siva Kaneswaran's Star Wars Wedding -- The Wanted Singer's Dream Is Going Down

"The Wanted" singer Siva Kaneswaran convinced his girlfriend to throw a "Star Wars"-themed wedding ... and he didn't even have to use Jedi mind tricks.

Siva's fiancee Nareesha McCaffrey agreed to the gimmicky nuptials -- actually we're told he just wore her down -- but the one outstanding sticking point was the dress.

We're told his fiancee refused to walk down the aisle in a slave Leia costume. She's insisting on a traditional wedding dress.

Their dog/ring bearer was not so lucky ... he'll be wearing a Chewbacca outfit.

Groomsmen will wear "Star Wars" cuff links and boutonniere's emblazoned with the movie's logo -- along with other fun stuff.