The 49-year-old Channel 4 favourite looked stunned when the actress, 21, seemed to forget that she was on live television in the middle of the day.

Florence, who is famous for her roles in Lady Macbeth and Marcella, joined Tim and his co-host Simon Rimmer, 54, to help whip up a fillet of beef with anchovy butter and Alpine potatoes.

However, things soon took an awkward turn when Tim asked Florence about how she had celebrated her 21st birthday this year.

“Not that well,” she responded, adding: “I was doing a film at the time so it all went a bit t**s up.”

Tim let out an audible gasp as the star appeared to fail to realise her blunder, continuing: “I organised something and it went downhill.”

The Sunday Brunch presenter stared down at the table uncomfortably as she explained: “But my friends saved it.”

“Okay, that’s good,” he interjected, hurriedly moving the conversation on by asking: “Do you do any cooking?”

The show regularly features minor hiccups and dramatic moments as the hosts try to keep the live broadcast in hand.

Earlier this month, guest Al Murray stormed off amid a feud with Simon when a heated argument about turkey boiled over.

Sunday Brunch continues next Sunday at 9.30am on Channel 4.