Robson made a surprise appearance on the daytime show to offer her support to her former co-star, who was speaking about her recent dramatic seven-stone weight loss.
Praising Quirke, she joked: "What have you done with all your old clothes? I'll have those! You look fantastic, you really do.
"I've been hiding in a wardrobe all morning! But I've never seen Pauline look this good before - she's always been beautiful. Maybe it'll spur me on to do something now."
A tearful Quirke said: "I've been texting her and everything, and this morning I thought it's the first time she's never rung or anything for my birthday!
"And I texted her because I'm renewing my wedding vows next month and she's not got back to me and I was just going to text today to ask 'are you OK' because I was worried!"
Birds of a Feather ran for nine series on BBC One between 1989 and 1998.
Lesley Joseph, who also starred in the sitcom, appeared via videolink to send a congratulations message to Quirke.
> Joseph backs 'Birds of a Feather' return
> 'Birds of a Feather' to return?