Yes, they really do call her that. It's not just a shorthand term, dreamt up by the media. It's official - I have it here, printed on my invitation. "A Reception in Honor of the First Lady." Note also the American spelling.
Once you get on one invitation list, for whatever reason, I suspect they hand your name and address around. A bit like double glazing firms or insurance companies.
My wife on this occasion refused to go. She hates standing around, smalltalking, when she could be at home reading a book. So I went on my own, mainly because I had a personal question I wanted to ask Mrs Clinton. If, of course, I got the chance.
At Downing Street, each guest on arrival was introduced personally to the PM, and we got our little moment of intimate chat.
Would I manage to get intimate with Hillary? Or would the American heavies drag me away as soon as I started to ask about her and Bill?
There were police everywhere outside the Embassy. Once inside, I was met by a very official-looking woman in uniform with a badge saying "Pinkerton", who said, "Take your hands out of your pocket."
I was wearing my white suit, once again - well, it is my only suit. My wife had warned me not to slouch or put hands in pockets, but this did seem a bit bossy. Turned out to be a body check, before going through an airport-style security barrier.
On the way into the reception room I met Salman Rushdie.
"You must be used to this," I said. "All this security stuff."
When he came to my house, a couple of years ago, he had three heavies with him - one of whom went off and left his mobile phone behind.
Salman stood on the edge of the reception room, waiting for his partner to arrive, so I went into the scrum determined to mingle.
There were about 200 people present. Roughly the same number as at Number 10, I spotted Richard Branson, once again - he must get invited everywhere - but without his wife this time. He was talking to Sir Brian Mawhinney. I suppose he'll go anywhere these days, now he's out of government.
I was greeted by Helen Mirren, very warmly, which was nice. Then she introduced me to her partner, a hunk of an American called Taylor something, who is a film director. I wondered what sort of drinks and eats we would get. Three to five on a Sunday afternoon is a bit early for real drinks. "Perhaps it'll be toast and marmite," said Helen.
I talked to my local MP, Glenda Jackson. I commiserated with her about some rotters in the local Tory party in Hampstead who are offering a reward, according to our local paper, for a photo of her smoking. I suggested she bought a packet of those sweet cigarettes, the sugary ones with the red tips, get herself photographed with one, then sue. Har har, she said.
David Bailey was there, looking his usual scruffy self, though he did have a tie on, undone, and was carrying a camera. "How did you get that in?" "Just walked in with it," he said.
I then got another kiss from a lovely young lady - Sarah McCauley, current squeeze of the Chancellor of the Exchequer. I have known Sarah since she was at school with my older daughter. Don't get worried, Gordon.
"So are you getting married?" I asked. "Come on, you can tell Uncle Hunt." "I don't know," she replied. Are you not getting married to him then?" I don't know," she said. But she did say she would invite me to a drinks do at Number 11.
I then noticed there were two babies present - both aged less than six months. One was Salman Rushdie's, being breastfed by his partner who had at last arrived. The other was Zola. No, not the footballer, but Ian Hargreaves's baby. He's the editor of the New Statesman, and was there with his wife, who is a Baptist Minister. "Shouldn't you be working," I said, "as it's a Sunday?"
I took a service this morning," she replied.
We all stood around for about 45 minutes, making such idle chat, till at last there was a flurry and Mrs Clinton arrived, followed by some men in suits, with electronic earpieces. She was wearing a blue, buttoned- up jacket, a black skirt and black stockings. Big blue eyes, which I hadn't expected, and a clean, bright, eager expression.
She was introduced by the new American Ambassador, Philip Lader. He was a bit pompous and formal in his speech, lavishing praise on the First Lady, which, of course, is part of his job. Behind him Mrs Clinton was making a funny face, clutching her heart in mock horror. That was nice.
Then she spoke to the assembled guests, without notes, and was witty and amusing. She said she'd had the weekend at Chequers with Tony Blair and his wife - whose name she pronounced "Sherry" - and said they had been invited to Washington by the President. The date would be announced very shortly. She then made a joke about being in touch with Mrs Roosevelt, which all the Americans present laughed at, but I didn't quite get. Apparently there has been some newspaper report saying Hillary has been in extrasensory contact with Mrs Roosevelt.
After her speech, the Ambassador said Mrs Clinton would try to get round as many guests individually as possible. An enormous queue soon formed. Oh no, I thought, she'll never get round us all, and anyway I want to get home to watch the second half of the Everton/Southampton match on telly. On the other hand, I'll probably never get to meet her in the flesh again. So I joined the queue, both elbows going. I waited about half-an- hour, then, oh rapture, I got to talk to the First Lady - one to one.
The Ambassador introduced me, explaining I was a writer. So he'd done his homework. We shook hands, and I said I just wanted to ask her one question. About her and the President, actually ...
For a moment, I sensed a flicker of worry from the Ambassador, wondering what I might be going to ask.
I explained that I publish and write a guidebook to the Lake District, and in it I list all the famous people who have stayed in Lakeland, including President Woodrow Wilson. Well, someone told me that she and Bill, sorry, Mr President, had had a holiday in Lakeland when they were courting. I'd never been able to verify it. Was it possibly true?
"It sure is true," she said. "We got engaged there.
"Brilliant," I said. "What a good choice. Whereabouts?"
"Oh, I know it well. We live in the next valley. Which end of Ennerdale?"
"I don't remember exactly. But it was a beautiful day. We'd walked and walked - and then Bill proposed.
"Was he at Oxford at the time?"
"No, no. It was just after we had both graduated from law school. Then we went off to England for a holiday. And he proposed."
"And did he produce a ring?"
"Well, I didn't immediately accept his proposal. Not there and then. I thought about it for a few weeks, then I said yes."
Ah, isn't that lovely.