London Irish have made a poor start to the new season and have won just one of their first five matches.
Hewat is eager to get over to England to help his new club climb up the table.
"That's the plan. If I can come across and help us win a few games then that's what I want to do," Hewat said.
"I can't wait to get into it. I'm really looking forward to this challenge."
A relatively late-bloomer to rugby, Hewat has starred for NSW during the past three Super 14 seasons, amassing 636 points to sit second on the franchise's all-time point-scorers' list behind former Australia star Matt Burke.
Although he is disappointed at never getting a chance to play for the Wallabies, the 29-year-old said he was not bitter at continually being snubbed by national selectors.
"Playing for Australia is something that didn't happen for me but it's not something that haunts me," Hewat said.
"It would have been great to get that chance, and an honour, but it was something that was out of my control to a large extent.
"All I could do was play well for NSW and I felt I did a reasonable job there.
"If someone had told me a few years ago that I'd play 50 games for NSW, I would have laughed.
"I feel grateful to have been given that opportunity."
Wallaby great Mark Ella is mystified as to why Hewat never got a chance to don the green and gold of Australia.
"I can't understand why he didn't have a shot at it," Ella said.
"It seems strange he wasn't picked. I feel he earned the right to have a shot at it. We just needed to see him at that level, once and for all.
"He makes the most of an opportunity and rarely lets a team down."
Former Wallaby coach and current Springboks assistant, Eddie Jones, defended his decision not to pick Hewat during his time in charge.
"It's been well documented in the past that I haven't been his biggest fan but I have no regrets at all (about not picking him)," Jones said.
"There were areas of his game that he had to improve and didn't."