Heather Morris has shot down reports she's undergone breast enhancement surgery.

The Glee actress, who plays cheerleader Brittany in the all-singing, all-dancing show, has been pictured looking curvier than usual in recent weeks, prompting speculation she had gone under the knife to make her bust bigger.

But Morris has laughed off the gossip, insisting "great" underwear is her secret to a fuller chest.

She tells American Cheerleader magazine, "Not that I need to clear this up, but I did think it was funny when there was a picture taken where I had a great bra on and they said I got a boob job because I was famous now. I was like, 'What?'"