The pair, who have been together for a year, reportedly married over the weekend, a source told US magazine People.

While representatives for both stars had no comment, the source said the ceremony took place on Sunday evening at the Boone Hall Plantation in Mt. Pleasant, South Carolina, one of America's oldest working plantations and where the romantic movie The Notebook was filmed.

The reception was held in a white tent set up at the plantation.

"Ryan and Blake wanted the event to look and feel like home," wedding planner Tara Guerard told E! News.

"With decor and live music, we all created the charm, elegance and magic of times passed."

Blake wore a custom Marchesa with “a hand-draped silk tulle bodice adorned with crystal and rose gold embroidery”.

Her bridesmaids also wore custom Marchesa gowns and all wore custom Christian Louboutin shoes.

Wedding plans had been underway since June when Tara accompanied the pair on a trip to look at venues.

The Gossip Girl star’s mother and sister were spotted in town in the lead up to the event, and a source confirmed that Blake, 25, and Ryan, 35, had dined in nearby Charlestown with Bette Midler earlier in the weekend.

While the wedding was kept top secret, it has emerged that the cake was driven down to the venue from Virginia, and that Blake’s good friend Florence Welch, from Florence and the Machine, performed three songs.

The couple, who co-starred in The Green Lantern, have kept a relatively low profile since purchasing a home together in New York earlier this year. This is Blake’s first marriage. Ryan was previously married to actress Scarlett Johansson, but the two divorced in 2010 after two years of marriage.