Mark, who recently confessed to cheating on his wife Emma Ferguson with 10 women, was the butt of a number of jokes made by Robbie, who was performing in London.
He said: "This is going to be one of the best nights of my life, do you know, it's so nice to be the only member of Take That not in trouble this week. That's a surprise isn't it?"
Later on, the 36-year-old singer said his song 'Rock DJ' reminded him of Mark - who has since gone into rehab for an alcohol problem.
He said: "Me with the floorshow, kicking with your torso. I'll be like Mark Owen by the time I come off after singing that. I shouldn't have said that, should I?"
Robbie also admitted he was afraid to let go on stage at the concert for UK radio station Heart because he had put on weight.
He said: "I'm a little porky and have to do sexy tonight and what did I put on? A cardigan. You wouldn't want to see my body without it. I've got a real complex now about dancing - I used to be really good."
Despite his jokes, Robbie - who has overcome his own battles with addiction - has been supporting close friend Mark through this difficult time, along with the other members of Take That, Gary Barlow, Howard Donald and Jason Orange.
A source said: "Mark has confessed to having issues with alcohol and with his own substance abuse past, Robbie is the perfect person to offer him support."