Nicola McLean thinks Heidi Montag will make "the most amazing mum."

Nicola McLean

Nicola McLean

The 36-year-old former glamour model spent three weeks with the former 'Hills' star at the beginning of the year when they were both locked inside the famous 'Celebrity Big Brother' house for the 17th series but, although they locked horns numerous times on screen, the blonde beauty has taken to her Instagram account to congratulate her pal and her husband Spencer Pratt on the birth of their son Gunnar.

Alongside a photograph of Heidi with her blossoming baby bump, Nicola said: "I had the honour of living with this beautiful soul and have no doubt she will make the most amazing mum ( mom) congratulations @heidipratt and @spencerpratt will be the coolest dad ( don't put the heated seats on, on the school run) love you both (sic)."

Heidi and Spencer - who got married in 2009 - announced the birth of their little one this morning (02.10.17) but the blonde babe admitted her labour was "hard."

Heidi, 31, shared: "We are so blessed to have a beautiful healthy baby boy. It was the hardest and most rewarding experience."

Whilst Spencer, 34, added: "[It's] officially the most lit day of my life."

And, although Gunnar is only a few hours old, Spencer has big plans for his son as he previously revealed he wanted his child to sign up to social media.

He said previously: "This kid will have an iPhone at birth. I'm gonna teach this kid how to Snap when they're born, like, 'Put your finger here.' You walk around, everybody's making their own content all day long. We live in a new world where everyone's a fame w***e, so I'm happy to let him be at an advanced level. I would just like my baby to be a professional content maker."