Nicki Minaj was stunned and trembling when Madonna planted a kiss on her lips during a video shoot, insisting she was convinced it was a dream.

The Super Bass hitmaker teamed up with the Material Girl to film a promo for their track Give Me All Your Luvin' in December (11), just days ahead of Minaj's 29th birthday.

Madonna shocked the star by presenting her with a cake and kissing her full on the lips as an early birthday gift - and Minaj admits the saucy surprise left her speechless.

She tells U.K. talk show host Graham Norton, "You can't really call it making out. She kissed me but I didn't kiss her. I wasn't expecting it and was shocked like everyone else. I was shaking and thinking, 'Is this really happening and why is she doing this?'

"It was the strangest thing, except she had very soft lips... I guess you could say that (she's a good kisser), but we didn't hang around in that lip locking thing. It wasn't all drawn out and crazy."