Belfast-born Stirling, 28, was signed by the Knights in the player draft on 10 September.

O'Brien, 34, received a late call-up to the Knights squad last week.

"I'm delighted to be heading over with Stirlo [Stirling] to Sharjah to join the Kandahar Knights," said O'Brien.

"The call came late last week that I was being offered an opportunity in the APL and it took a matter of seconds for me to say yes."

Brendon McCullum will captain the Kandahar Knights in Sharjah

McCullum to captain Kandahar Knights

O'Brien has previously played in franchise T20 competitions all over the world and will be part of Knights squad captained by New Zealander Brendon McCullum.

"He's a captain who encourages his team to have confidence in yourself and express yourself on the field, whether with bat or ball in hand," added O'Brien.

"When you are sitting in a dressing room surrounded by some of the world's elite cricketers, you can learn so much in their mindset and approach to playing and training.

"That's the beauty of franchise cricket - you get to play with a wide range of cricketers that you would previously never have had the opportunity to."

McCullum was a former team-mate of Stirling at Middlesex.

More T20 exposure 'will benefit Irish cricket'

Stirling believes the presence of him and O'Brien in the tournament will benefit Ireland's future T20 endeavours.

"With the World T20 Qualifier around the corner next year, I think it's really important to have Irish players at these tournaments, bringing the experiences gained back into the Ireland set-up," said the Middlesex opener.

"We've seen how it has improved the Afghanistan side inside two years where they have had a handful of players play in the Big Bash and IPL getting used to playing day-in day-out against the best in the world."

O'Brien's brother Niall has turned down the offer of a batting coach role with the Knights.