The Valbrects were a species of shapeshifters.
In May 1944, the Valbrects led by Reginta sought to invade Earth while the World War II weakened the planet, gain control of its minerals and ores and enslave the human race. They began by infiltrating a US Army base commanded by General Michael Heyman, with plans to replace the entire US Army and seize control of the planet. The Twelfth Doctor exposed them and Colonel Preston led the defence of the base. The Doctor forced the Valbrects to leave Earth by threatening to blow up their ship with an American bridge-buster bomb. (PROSE: Base of Operations)