Justin Timberlake regrets his Grammy Awards performance with a rejected American Idol singer, insisting event organisers took advantage of his "nice guy" attitude.

The Sexyback singer performed a medley of tunes with Robyn Troup, who won a TV contest called My Grammy Moment to land the chance to perform with Timberlake on music's biggest stage last month.

Timberlake tells men's magazine Details he considered pulling out of the performance, but feared he'd left it too late.

So, even with a heavy cold that prompted him to withdraw from a pre-Grammy party performance, he agreed to go through with what he felt was a bad idea.

He says, "I'm the nice guy who follows through on the things he commits to. But I don't know if I'll be going through that sort of thing again."

"I feel like the Grammys used me for ratings."