The 'You Know Me' star asked Field to marry him on Tuesday because he couldn't wait until New Year's Eve, The Sun claims.
"He just couldn't help himself," a source said. "He's like an excitable puppy. He wanted to wait until midnight on New Year's Eve to pop the question, but just couldn't hang on. So he proposed at home on Tuesday night. Despite all the previous speculation about them getting hitched Ayda was still very surprised. She was thrilled and said yes straight away."
In November, Williams proposed to Field during a radio interview. However, he later insisted that it had been a joke.
> Williams: 'Field is a wonderful person'