Britney Spears’s ex-husband was arrested while crashing her wedding site in southern California, authorities say.

Captain Cameron Henderson of Ventura county sheriff’s office said officers responded to a trespassing call after 2pm on Thursday.

He said the pop singer’s first husband, Jason Alexander, was detained at the site of the ceremony.

Alexander was arrested after officers noticed he had a warrant for his arrest in another county, Henderson said.

Earlier on Thursday, Alexander broadcast a live video from his Instagram account as he approached the event security.

Walking around what appeared to be a mostly empty but decorated house and gardens, he told them repeatedly Spears had invited him.

Variety reported that deputies were still investigating what had occurred, and would determine if additional charges will be brought against Alexander in relation to the trespassing allegation.

Spears was previously also married for two years to dancer Kevin Federline, with whom she shares two sons, aged 14 and 15.

Spears and her fiance Sam Asghari were reportedly expected to marry on Thursday. The couple met on the set of a music video in 2016.

They announced their engagement in September last year, shortly before Spears won a legal battle with her family and was freed from a 13-year conservatorship in November.