The non-denominational ceremony was attended only by the bride and groom, both barefoot and wearing white.
"We didn't want to wait another day to get married," Spelling tells PEOPLE.
Adds her new husband, "I've never had as much of a desire to get married and make a woman my wife as I've had with her. The feeling is overwhelming. We're soul mates."
Spelling, 32, and McDermott, 39, met last summer in Ottawa while filming the TV movie Mind Over Murder. At the time, she was wed to actor-writer Charlie Shanian, and McDermott was married to his wife of 12 years, Mary Jo Eustace.
In September, Spelling announced her split from Shanian, and McDermott filed for divorce from Eustace. Spelling's divorce became final last month.
McDermott proposed to the So NoTORIous star on Christmas Eve in Toronto, Canada. His sister put out lights leading to a table for two surrounded by decorated Christmas trees. The couple rode up in a horse-drawn carriage, and McDermott presented Spelling with a diamond and sapphire ring.
"It was so magical. All the stars aligned. I have never been happier in my life," McDermott told PEOPLE at the time.
McDermott has since shown his love for Spelling with tattoos, including one on his wrist that reads "Truly, Madly, Deeply, Tori" and another on his shoulder: a portrait of her.