"Those who can find compassion now are the ones who deserve to watch you continue to grow. We are all here to support you and make each experience easier. Your talent and good heart will never lead you wrong.
"Love you and so proud of you always :) G (sic)."
Gigi's message came just days after the pair reconciled following a reported split earlier this month, although neither have addressed the break-up reports.
Zayn was due to give his first solo performance in the UK since quitting One Direction last year at the Summertime Ball but left fans devastated after failing to show up.
And he later revealed that an anxiety attack was the cause of his failure to perform.
He wrote on Instagram: "To all those people who have been waiting to see me perform at the Capital Summertime Ball today..
"I flew into the UK last night to appear in my home country in front of my family, friends, and most importantly my UK fans.
"Unfortunately my anxiety that has haunted me throughout the last few months around live performances has gotten the better of me... with the magnitude of the event I have suffered the worst anxiety of my career. I cannot apologise enough but I want to be honest with everyone who has patiently waited to see me, I promise I will do my best to make this up to everybody I've let down today "I know those who suffer anxiety will understand and I hope those who don't can empathises with my situation (sic)."
- Bang! Showbiz