Seth MacFarlane stopped by “Jimmy Kimmel Live!” on Monday and shared one of his fondest family Christmas memories.

The “Orville” star told the late-night host that one holiday season, he and his sister brought marijuana into the house to see if their parents would smoke it with them.

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“My parents had talked for years about how they did a lot of drugs in their younger years,” MacFarlane explained, and so he thought it would be a fun, festive treat for the family to get high together.

“With very little coaxing, they [his parents] partook,” the “Family Guy” creator laughed. The weed went down well but MacFarlane soon regretted his decision.

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“My mother was just laughing a lot. And my father turned to me, and I instantly regretted the whole enterprise, he said, ‘God, Seth, you know, this is the first time that you and I have been stoned together as father and son.'”

As for this holiday season, MacFarlane just hosted his big annual celebrity Christmas party, which was attended by Leonardo DiCaprio and Bill Nye the Science Guy, whom Kimmel presumed didn’t arrive together.

“You know, actually, Bill and Leo were together. I don’t know what’s going on there,” MacFarlane joked.

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The former Oscars host also revealed his favourite and least favourite Christmas songs.