Supermodel Heidi Klum just can't keep her hands off her boobs in a new advert for lingerie chain Victoria's Secret. In the 30-second clip, Heidi pretends her breasts are machine guns, calls them 'great knockers' and even does a bit of yodelling. Wearing a black bra, the 34-year-old stunner jiggles her 'guns' and generally spouts a lot of nonsense. But she looks pretty hot, so who cares? After pointing out that her nipples stand to attention when it's cold outside, she squeals: 'I've got great knockers!'