The Get Him To The Greek star, who is engaged to pop star Katy Perry, said he was mad about Moss, 36.
And he said he still has her number - saved as 'Grimy Tyke' in his contacts list - to prove to himself that he really bedded her.
He said: '[That] is what I called her in an attempt to punctuate the endless flattery and awe. I keep it as a digital memento, just to assure myself that it wasn't a dream.'
Writing in his new memoir, Booky Wook 2: This Time It's Personal, Brand, 35, said he was in love with the supermodel.
'What no one realised, not Kate nor the red-top tabloid press, was that far from viewing her as a conquest, I was absolutely smitten. When I clumsily ballsed it up by flatly telling journalists, 'I was just larking around,' she wisely withdrew and I had enough sense to stop calling her.'
Brand is set to wed I Kissed A Girl singer Perry in India today (Saturday).