The New Tricks star's birth certificate was allegedly uncovered by a Sunday newspaper at the weekend, indicating that she is about to turn 52 rather than 50 as she has been stating.
Experts have now suggested that the discrepancy is unsurprising due to the prevalence of ageism within the TV industry.
One casting director, Simone Reynolds, told The Guardian: "The pressure on [actresses] is enormous. There is a huge emphasis on youth, and there just isn't the same number of parts for women as there is for men.
"Once you hit your 30s you notice there are fewer parts. When you're in your 40s, it's really quite difficult, and as for your 50s..."
Another, Paul De Freitas, added: "I'd like to think age doesn't matter, but it does. You see it now when women on TV are being fired for getting older, so it doesn't encourage people to be honest. We live in an ageist society."
Redman, who previously starred in At Home With The Braithwaites and Honest, has already admitted that she fears losing out on parts due to her age.
Speaking last month, she commented: "It is all very good being in New Tricks and for as long as that goes on, that is fine. Outside the roles are not there. In our industry there is never going to be anything other than young and beautiful."