Guest Lorraine host Fiona Phillips has been accused of fawning over her male guests.
Fans of the ITV show asked for the "flirting" to stop when Fiona, 55, interviewed Hollywood star Dave Franco, 31, on Thursday morning.
The former GMTV star has been standing in for Lorraine Kelly who is off enjoying her summer holidays.
Viewers said that it made uncomfortable viewing.
Others rallied to her defence.
Fiona's not the first TV host to be accused of flirting, with Susanna Reid usually in the frame.
The Good Morning Britain host has sent viewers into a frenzy with her interviews with Arctic Monkeys frontman Alex Turner, then Prime Minister David Cameron and Dracula Untold star Luke Evans.
Meanwhile, it's also been announced that Lisa Snowdon will be filling in for Lorraine a week.
The former Strictly Come Dancing star said: "I'm so excited to be stepping into Lorraine Kelly's shoes for a week. I'm a huge fan of the show, so it's a real honour for me to be asked to cover. The lineup for the show next week is looking fantastic as well, so I really can't wait!"
Lorraine's editor Sue Walton said: "I'm delighted to welcome Lisa to the Lorraine show for a week - millions enjoyed waking up to her unique brand of warmth and fun when she hosted breakfast radio."