A "shocked" Thomson told the Sun Friday morning she expects Ford to apologize.
"At the end of the day I hope he changes his behaviour and he doesn't do this to someone else," she said.
"I asked him why he wasn't at the mayor's roundtable … he was laughing and said, 'I was in Florida, you should have been with me, my wife wasn't there.' "
Thomson said she thought the comment was "weird."
"I just kind of fluffed it off and then we posed for a picture and he grabbed my ass and I said OK this is not Rob … I thought there was something really wrong with him."
Mark Towhey, Ford's chief of staff, said the mayor is "shocked" by the allegations and disgusted someone would make them.
"We'll consult with legal counsel, we've already had one conversation - we'll make a decision at some point," Towhey said.
"I didn't hear the conversation. I can tell you I was there throughout, the mayor had me there plus three additional staff and a driver, the three staff were within earshot of him the entire time. They never heard any of this."
"The mayor commented about her still having the same (dreadlocks) hairstyle, they laughed. She asked him if he would support her subway tax, he said, no. I know that I was 20 feet away watching all of this stuff go down, she was very happy - it appeared to me as laughing and smiling."
Towhey stressed Ford was in Florida for the last week with his wife and children and confirmed no one complained to him or any other member of the mayor's staff at the event.
"The first that we heard she was concerned about anything at all was Twitter last night," he said.
The chief of staff said Ford had no alcohol to drink at the event.
"The only thing he drank when he was there was about four glasses of water that I brought him and a bottle of water that the staff had," he said. "It was hot and so he drank a lot of water."
A statement from Ford is expected later in the day.
Thomson first raised the issue on her Facebook page just after midnight.
"Thought it was a friendly hello to Toronto Mayor Rob Ford at the CJPAC Action Party tonight until he suggested I should have been in Florida with him last week because his wife wasn't there," Thomson wrote on Facebook. "Seriously wanted to punch him in the face. Happy International Women's Day!"
By 6 a.m. Friday the photo had more than 300 comments on it and had been shared several hundred times.
Thomson went on to add a few other remarks to the photo.
"I've never seen him so out of it. I know I shouldn't be pissed but after spending 10 months on the campaign trail together you expect a little bit of respect at the very least for my husband," she wrote.
She told another Facebook user to "guess where his hand was in this picture? I must go shower...."
"Anyone who talked to him tonight could see he was out of it - I'm venting because I thought on the respect for women level he was better than that," she told another Facebook commenter.
But then Thomson wrapped up her comments with what could be a fairly incendiary allegation.
And the predictable response, complete with condescension:
Originally Posted by ROB FORD
Last night I had the pleasure of attending a wonderful event to support the Canadian Jewish Political Affairs Committee.
“This is an event that is attended by numerous political leaders and where I have been a guest in the past.
“Early this morning, false allegations were made regarding a number of disgusting actions. I am shocked, dismayed and surprised. I can say without hesitation that they are absolutely, completely false.
“What is more surprising is that a woman who has aspired to be a civic leader would cry wolf on a day where we should be celebrating women across the globe.
“This is a day we should all take the time to reflect upon the women in our lives and in our society. It is a day when we can envision the changes we want to make in our communities to ensure that all people are equal and that violence and discrimination against women comes to an end.”
In her radio interview on Monday, Thomson also suggested Ford was high on cocaine when he allegedly grabbed her buttocks.
“Did you think that he was on cocaine, is that what you had said to our producer?” one of the KiSS DJs asked Thomson on the air.
“I thought he was, yes, but I don’t know,” she said. “What are the signs of cocaine use, I looked it up [on Google]. And it’s, you know, sweaty, talking quickly, out of it, arrogant. Like all these things were on there.”