Tweddle, who plans to retire after competing on the bars and floor at London 2012, said: "This is my third Olympics and with it being on home soil it's definitely the most special.
"After 2008 I wasn't even sure I would carry on, but the huge support for London and the enthusiasm of the public has really motivated me and inspired me to carry on training hard."
Ollie WilliamsBBC Sport
Beth Tweddle has made it to London 2012 at long last, having fought off a succession of injury scares - and even slept with an ice machine on her leg at night to reduce the swelling.
But Louis Smith is probably, on paper, Britain's best hope of a gold medal at the Games. His score of 16.375 on the pommel horse at last month's British Championships would be incredibly difficult for any rival to get near if he reproduced it in a month's time.
The problem is, his event is fraught with danger - one slight error and he'll fall. If he goes for his toughest routine, it may be all or nothing.
2008 bronze medallist,
set a new personal best of 16.375 on the pommel horse at last month's trials, a score his rivals may struggle to match at the Games.
"Now we've got to do the business at the Games, which we're all capable of," said the 23-year-old.
"It's just been a crazy four years since Beijing, for me and especially for gymnastics in this country. I'm not sure anyone ever expected such rapid development and it's such a positive thing for everyone involved in the sport. Now we have a chance to really show how far we've come."
Keatings, who has struggled with injury over the past couple of years, has been overlooked for 19-year-olds Max Whitlock and Sam Oldham, leaving the 22-year-old "angry" at the decision.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.