Ashton worked under Farrell during the RBS 6 Nations when the Saracens coach was seconded to England as their attack coach.
That link-up at international level will come to an end after the RFU were unable to come to a deal with the Premiership champions to secure Farrell's services on a permanent basis.
But Ashton will have the chance to continue learning from his fellow Wiganer and cross-codes convert when he leaves Northampton at the end of the season to go to Saracens.
"I have to be selfish and say that, yes, I'm really pleased that he's staying as he was a big part of me wanting to go to Saracens in the first place," Ashton told the Telegraph.
"Andy was also instrumental in getting my mate from school days, Joel Tomkins, down. It's unfortunate Faz can't do both jobs because he had such a big impact at England."
Ashton's reputation has gone through the mill in the last 12 months- equalling an RBS 6 Nations record of six tries in the 2011 Championship and also as joint top try scorer in the World Cup.
But off-the-field antics meant he left New Zealand under a cloud before his protracted move to Saracens left a bitter taste in the mouth of the Saints' support while he endured a try-less 2012 RBS 6 Nations.
And the 25-year-old admits he has had to grow a tough exterior over the last year.
"It does hurt that I'm seen as arrogant by some people and it's beyond me how it comes to that at times," Ashton says.
"The signing for Saracens came to be unfortunate in the way it eventually all came out, but it wasn't meant to be like that at all.
"There's nothing much you can do about perceptions apart from keeping on doing your best. I do care. I don't want people thinking negative stuff about me. I'm a naturally relaxed, happy sort of guy.
"So, yeah, there was a point when it all got turned on its head. There was me, scoring tries, glad to be doing so, and then I'd get slammed for celebrating too much.
"I came away from the World Cup on a bad note but the silver lining on a very dark cloud was that I was joint top try-scorer in the tournament.
"Highs and lows are part of sport. You've got to be tough, get through it, there's bound to be a plateau. You get stronger. I'm more resilient than I was."