Miranda Kerr thinks Katy Perry is "amazing".

Miranda Kerr

Miranda Kerr

The 37-year-old model, who was married to Katy's partner Orlando Bloom between 2010 and 2013, sent a sweet message to the 'Roar' hitmaker via social media after she returned to work on 'American Idol' after giving birth to daughter Daisy in August.

Katy posted a photo of herself on Instagram in a cow-printed dress, with the caption: "MUTHA MILKS is back to werk @americanidol and it's udderly ridiculously MOO-ving already!

"Not pictured: my pumping breaks (shout out to @csiriano for the incredible custom costume."

Miranda commented on the image: "Omg you're amazing! Love you."

The star previously revealed that she "couldn't wait" to meet Daisy after Katy and Orlando announced her birth.

Miranda wrote: "I'm so happy for you guys. Can't wait to meet her."

Kerr and Bloom share son Flynn, nine, while the model has two more sons – Hart, two and Myles, 11 months – with Snapchat boss Evan Spiegel, who she wed in 2017.

Kerr previously confessed to being a big fan of the 'Firework' singer as she opened up about co-parenting with Orlando.

She recalled: "My family went to see Katy when she was in Australia and she really took care of them – they loved it."

Miranda revealed that Flynn is the "number one priority" for her and the 'Pirates of the Caribbean' actor.

The model added: "Flynn is our number one priority, [so we're] just open and transparent with each other. We are very blessed as we all enjoy each other's company."