Bradley (48), who starred as Mr Doyle in Trainspotting sequel Trainspotting 2, was shot and killed on Chester Street in the Capital's West End on Wednesday night.
Close friend and fellow Hibs supporter Irvine tweeted on Thursday morning, to say his 'heart is broken', before thanking Bradley for 'helping me see the world in a kinder and wiser way.'
Writing on Twitter, Irvine said: "Bradley John Welsh, my heart is broken. Goodbye my amazing and beautiful friend. Thanks for making me a better person and helping me to see the world in a kinder and wiser way."
Bradley is a past British ABA Lightweight boxing champion.
He has run charity projects in the city to help young people stay fit and out of trouble through his Holyrood Boxing Gym and was also involved with Edinburgh charity Helping Hands.
In 2017, Bradley secured a role in Trainspotting 2 thanks to a successful Guinness World Record attempt that saw him spar with 360 people in succession, including director Danny Boyle.
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