DYNASTY star Linda Evans is hiding a tragic secret shame — the ­former TV beauty is on probation after a drug arrest in Washington state!

Now 74, Evans was pulled over for driving while falling-down-stoned on more than a half-­dozen powerful painkillers — and when cops searched her SUV they found 29 pink pills! Amazingly, the bust was caught on police video, which was exclusively ­obtained by GLOBE!

On the tape the blonde, who quit Hollywood and joined the cult-like Ramtha’s School of Enlightenment, looks dazed, confused and is unable to stand without support. Says a source who viewed the shocking video, “Linda was totally blotto!” 

Find out more this week about Linda Evans fall from grace in this week's GLOBE.