Comedienne Tracey Ullman once mistook Kanye West for a shop assistant and asked him about swimming trunks for her son.
She revealed the embarrassing story on The Graham Norton Show.
The star said: "I once took my son shopping for swimming trunks and in the shop I asked what I thought was a handsome sales assistant if they had what we wanted, and my son just kept saying: 'Mum, mum, mum.'
"It turned out to be Kanye West. That was embarrassing!"
Ullman returns to British TV screens for the first time in 30 years with Tracey Ullman's Show, for the BBC.
"I never got offered a job in this country until now. I'm really flattered to be asked," she said.
"I love it but people don't know who I am - they think I am Julie Walters!"
Actor James Nesbitt, who was awarded an OBE in the New Year Honours list, revealed he "ticked the wrong box", prompting the Palace to phone him and check if he wanted to decline the honour.
"It will be a nice day out at the Palace for me and my girls," he said.
He returns to TV screens in a new series of ITV's hit drama Cold Feet this year.
"We start in three weeks for a read-through, and I haven't seen loads of them for 12 years. The scripts look good and they tried to get us to do it for a number of years and they hadn't quite worked it out or sorted out the number of zeros on the cheques," he explained.
"It will be very exciting to do it and I can't wait to see what those characters are like now."
Harry Potter actor Ralph Fiennes said since playing the bespectacled wizard's nemesis, Lord Voldemort, he doesn't take on roles that require prosthetics.
He added: "But I knew the look (Voldemort's) was working when I walked past the script supervisor's five-year-old child, and when I looked at him he just burst into tears."
Fiennes told host Graham Norton fans often mistake him for Taken star Liam Neeson.
"I have been complimented for my performance in Taken 2 and Liam has been complimented on his English Patient," he said.
:: The Graham Norton Show airs on January 8 on BBC One at 10.35pm.