Matthew McConaughey has tied the knot.

The actor (42) married his long-time girlfriend, Camila Alves, in a quiet ceremony at their home in Austin, Texas on Saturday in front of some of their closest friends and family.

According to People.com, the celebration was a three-day affair on the couple's sprawling property. Guests lounged in hammocks, sipped beer and played lawn games throughout the weekend, and slept in luxury tents erected for the occasion.

Those working at the event had to sign a nondisclosure contract to ensure the nuptials remained private, BANG Showbiz reported.

For the ceremony, held at sunset on Sunday night, the actor wore a three-piece black Dolce & Gabbana tuxedo, while Alves wore a gown handmade by a favourite Brazilian designer.

"Matthew looked so handsome, like an old Hollywood movie star," a guest told People. "And Camila was just glowing and beautiful!"

McConaughey popped the question to Alves on Christmas Day but has previously said that he already feels married to the model with whom he has two children – Levi (3) and Vida (2).

He explained: "We have homes together, we have family together, we have kids, we've built a life together. So we've been living a married life this whole time.”