lend colour to
lend color to (something)
To embellish or add information or details to an account of something, especially to make it seem more credible or probable. He splashed mud all over his car and clothes to lend color to his story about being in the mountains all weekend. We cannot do anything that will lend color to our opponents' allegations about us.
lend (or give) colour tomake something seem true or probable.
1991 J. Rusbridger The Intelligence Game Nothing should be done that would lend colour to any suggestion that it [the Security Service] is concerned with the interests of any particular section of the community.