A high pressure multibore junction assembly and method for completion of a lateral wellbore using a high pressure multibore junction assembly, which comprises a tubular main leg and a tubular lateral leg. The tubular main leg is secured within a main wellbore and the tubular lateral leg is positioned through a lateral wellbore. The tubular main leg and the tubular lateral leg may be stabilized relative to each other as the multibore junction assembly is lowered into the main wellbore.