These wedding crashers were cops.

A groom was busted just moments from saying “I do” for failing to declare he was a registered pedophile.

Bradley D. Armstrong, 66, was about to tie the knot at the La Porte County Courthouse in Indiana on Tuesday when two officers burst in and busted him just before the ceremony started.

The bald, bespectacled groom — seen in a black cowboy shirt in his mugshot — was arrested in what the local sheriff likened to “something straight out of the ‘Wedding Crashers’ film.”

Armstrong was charged with falsifying a marriage license, a felony, for failing to reveal on his marriage license application that he is a convicted pedophile ordered to be on Indiana’s Sex and Violent Offender Registry for life, according to police.

It was not immediately clear who he was about to marry, nor if they knew about his disturbing background.

Armstrong was convicted with molesting a child in May 2002 and sentenced to seven years in prison, suspended, plus another seven on probation.

He was released less than two years later, in March 2004. It is not clear why he was allowed out so early.

Armstrong was booked at the La Porte County Jail on a $755 bail, according to police. He is already out of custody, jail records show – although it is unclear if the marriage is still on.