Rob Lowe and Michael J. Fox got pulled over by police during a star-studded bus trip because they were smoking marijuana.

The former 'West Wing' actor - who has been sober since 1990 - recalled a memorable charity initiative which saw a string of celebrities escorted out of their vehicle by cops after he and his pal attracted unwanted attention with their drug consumption.

Appearing on Ted Danson's 'Where Everybody Knows Your Name' podcast, Rob recalled: “There was a bus tour through California for Prop 65, which was about cleaning up our water system, and everybody on the planet was on it.

“But there were two different buses … We got pulled over for speeding, but also because Michael J. Fox and I were smoking pot out of the top of the Greyhound bus roof.”

“The cop pulled us over and it was like a clown car — out came Whoopi Goldberg, Cher, Judd Nelson, Michael J. Fox, Sarah Jessica Parker, Matthew Broderick, Robert Downey Jr., Jane Fonda, Danny Glover."

Asked why the bus was pulled over, the 60-year-old star admitted: “We had the top emergency hatch off, Michael and I, and we were smoking pot.”

The 'St Elmo's Fire' actor recently admitted one of the major reasons why he decided to get sober was when he ignored a call from his mom after his grandfather suffered a heart attack.

He told People magazine:

"The thing that really changed me was not being able to show up for my family and myself.

“I remember like it was yesterday – my mom telling me (on my answering machine) to ‘Pick up, pick up’ because my grandpa had had a heart attack.

“I couldn’t deal with it in the state I was in, and I needed to go to sleep to wake up so I could deal with it.

“Who doesn’t keep a bottle of Cuervo Gold (tequila) by their bedside table?

“That was the final wake-up call. I’ve been sober ever since.”