Her stepdaughter, Kim Kardashian West, tweeted: "How beautiful! Be happy, be proud, live life YOUR way!"
Khloe Kardashian declared: "We were given this life because you were strong enough to live it! I couldn't be prouder!!! Caitlyn ."
And daughter Kendall Jenner added "be free now pretty bird."
Among others to welcome Caitlyn - and her new Twitter handle (at)Caitlyn-Jenner - were Lady Gaga, who tweeted: "thanku for being a part of all of our lives & using your platform to change people's minds."
