The Devil Wears Prada star admitted she was "old enough to know better" in a statement.
The presenter hailed her Masked Singer co-star as "the nicest man and an ally of women”.
The service was also attended by celebrities including Paloma Faith, Helena Bonham-Carter, Nick Cave and Jonathan Ross.
The latest episode of Michael McIntyre's Big Show had Jonathan Ross at the centre of the dreaded prank segment.
"They were definitely a friend," the talk show host recalled.
"He’s not a celebrity. He’s a horrible human being," the ITV presenter said.
It seems Jonathan is less keen on embracing their familial link, however.
"I think occasionally Rita’s a bit confused."
Let's just say an orange and a hoover were involved.