'Nip/Tuck' Star Dylan Walsh Seen on Shocking Police Video After Major Car Crash

9/26 -- 12:07 PM PT -- According to a new police report -- obtained by TMZ -- Dylan’s blood test found no ethyl alcohol, and no impairing drugs were detected.

"Nip/Tuck" star Dylan Walsh looked rattled and shaken after his violent car crash ... he's seen on police body cam explaining to officers how the harrowing incident unfolded.

In the intense footage -- obtained by TMZ -- cops rush up to Walsh's SUV just moments after he swerved into oncoming traffic and slammed into two utility poles. Daily Mail was first to report on the bodycam.

Walsh's wife, Leslie, is seen getting treated for her injuries as she lays on the street ... and you can hear Dylan tell cops he was behind the wheel. He adds he isn’t sure how the crash happened ... saying he looked down, and the next thing he knew they were in the wreck.

Dylan says, "I was really tired, I was driving and it happened. I don't know how it happened" ... noting that he and his family were in the sun all day.

He also tells the cops he drank earlier in the day ... and officers go on to find an open cooler bag filled with booze and White Claw Hard Seltzers.

Someone who apparently witnessed the crash and claims to be familiar with Dylan and Leslie tells police the couple gets "extremely f***ed up" -- and says right after the crash, Dylan "instantly yelled at her to go get the bag out the backseat of the car."

However, it sounds like the person doesn't know what was inside the bag Dylan allegedly referenced, and the cop says he didn't get an "odor" from Leslie while speaking with her.

Dylan is later seen riding in the back of an ambulance ... and complies when an officer tells him a blood test will be requested to check for alcohol.