It is the third time that the ex-Family Fortunes host has got married. He previously tied the knot with Lynne Webster in 1990 and Britain's Got Talent star Amanda Holden in 1995.
Celebrities at the ceremony included Lionel Blair, Michelle Collins, and Loose Women presenters Carol McGiffin, Sherrie Hewson and Denise Welch.
Dennis and Nicholson have one daughter together, 19-month old Eleanor.
The 56-year-old's spokesperson told the BBC: "It was a wonderful occasion. Les and Claire looked sublimely happy and everyone thoroughly enjoyed the day."