Alan Partridge may have pitched some ridiculous TV ideas, such as Monkey Tennis, Inner City Sumo and Youth Hostelling with Chris Eubank, but sometimes truth is stranger than fiction – as viewers to ITV found out last night (13 November).

They were watching Gone to Pot, a show in which famous (ish) faces travel to the US investigating the benefits and drawbacks of the legalisation of medical marijuana. Among them was former soap star Pam St Clements, who took her research seriously.

Unless you're a doctor you can't have an opinion of marijuana without smoking some, which led to unlikely scenes in which Pat from EastEnders blazed it with a gaggle of nuns.

Christopher Biggins was also there.

Viewers were left dumbfounded as St Clements – who played Pat Butcher from 1986 until 2012 – got high and painted a cactus in a Californian nunnery.

She was joined by celebrity cohorts Biggins, footballer John Fashanu, Loose Woman Linda Robson and darts legend Bobby "Trebles for show, doubles for dough" George.

"WHY is Pat Butcher from EastEnders on ITV passin' the zoot and painting WHAT is happening," wrote one viewer on Twitter. "Pat Butcher and Bobby George getting mashed, will there ever be such a historic moment on tele again?" asked another.

Others were baffled, including Olympic gold medalist and former I'm a Celebrity contestant Samantha Quek, who tweeted a gif and said: "Italy not qualifying for the World Cup and Pat Butcher smashing a bong whilst painting a cactus?! ...I've seen it all tonight..."

"Pat Butcher smoking a spliff with a group of nuns is quite possibly the funniest thing I've seen on TV this year," said musician Dean Boroczky.