Father pens touching open letter to Ariana Grande

A father of three young girls is encouraging Ariana Grande to continue making "this crappy world a little less crappy" in a touching open letter.

The 'Problem' hitmaker has cancelled tour dates following the attack at her Manchester concert this week that left 22 people dead and dozens more injured.

US film producer Patrick Millsaps, whose daughters are aged 12, 12 and 13, has responded to Grande herself who tweeted she was "broken" and "so, so sorry" after the bombing.

"I'm afraid I need to set you straight girl... you don't have a dadgum [sic] thing to apologise for," writes Millsaps.

"You are no more responsible for the actions of an insane coward who committed an evil act in your proximity than you would be for a devastating natural disaster or acts of morons near your hotel."

Millsaps says due to his daughters' fandom, Grande is part of their family, and insists she shouldn't rush back to work while coping with the tragedy.

He even suggests she fire any manager who tries to contact her in the next 30 days.

"In your line of work, you have so many experts who are now 'strategising' what you should do next. These 'experts' don't have a freaking clue what you are processing right now," he says.

"Spend time with your God, your family and your friends who will give you space and support when you need it... When and only when you are ready, SING AGAIN. Music is the international language of peace. Every time you open your mouth and share that incredible God-given gift to the world, you make this crappy world a little less crappy."

Grande is set to perform in at Auckland's Spark Arena on September 2.