Baldwin is 54, and his bride, a yoga instructor, is at least 25 years younger than him. The wedding took place on Saturday at St. Patrick's Old Cathedral in New York City.
Matthew Hiltzik, a friend of the couple, said, "Hilaria Thomas and Alec Baldwin were married this evening at St. Patrick's Old Cathedral in New York City with family and friends sharing in the joy of the occasion."
While Baldwin wore a Tom Ford tuxedo, Hilaria Thomas - now Baldwin - wore a silk magnolia Amsale gown with cap sleeves, a keyhole back neckline, and crystal button accents. Also dressed by Ansale were Hilaria Thomas' mother and Ireland Baldwin, Alec's daughter.
During the hours prior to the ceremony, Baldwin Tweeted lines from an Emily Dickenson poem, "Resurrection." One Tweet read: "Was bridal e'er like this? A paradise, the host, And cherubim and seraphim The most familiar guest."
Meanwhile,the bride was doing her own nervous Tweeting in the days leading up to the wedding. On Tuesday, she Tweeted "Being a bride is stressful.... ayyyyyyy." Later that day she Tweeted, "If I buy one bride magazine, which should it be?"
The reception was scheduled to be held at New York University's Kimmel Center.
The couple began dating last summer. They announced their engagement in April. Baldwin was previously married to Kim Basinger (1993-2002), with whom he had Ireland.