The former One Direction star was being interviewed by awards show host Jack Whitehall during an interlude from proceedings when he discovered he was drinking a wine glass of neat tequila.
“He has literally gone off the rails,” Jack joked, before he then passed the glass over to Lizzo on the next door table to verify his claims.
However, Lizzo didn’t seem too bothered as to what it contained, as she proceeded to down its contents in one.
“Oh, my god! Yesss!” Jack shouted, as Harry got up out of his seat and cheered her on.
The pair have made no secret of their love for one another over the last few months.
The former One Direction star chose her hit Juice as his (steamy) cover when he played Radio 1’s Live Lounge last year.
He then got to perform the song as a duet with the lady herself last month during an event for US radio station SiriusXMini.
Harry jumped up on stage during the gig in Miami and not only sang along, but joined in the choreography too.
He previously called Lizzo “one of the most exciting artists working now”, saying during a Radio 1 interview: “I just think she’s amazing.
“She’s exactly what you want an artist to be, which is themselves.”
During Tuesday’s Brit Awards, Harry missed out on both the prizes for Best Male Solo Artist and Album Of The Year to Stormzy and Dave respectively.
Meanwhile, Lizzo lost out on Best International Female Solo Artist to Billie Eilish.
Harry, Lizzo, Billie, Stormzy and Dave were along among the performers during the ceremony.