Last Thursday, we had a story courtesy of The Enquirer, claiming that Michael C. Hall and his estranged wife Jennifer Carpenter are not getting along on the set of Dexter (Carpenter plays Deb, Dexter’s sister). I tended to believe the story, just because the gossip about Hall and Carpenter has been pretty consistent – he screwed around with Julia Stiles, Hall and Carpenter quietly separated, Carpenter began seeing other people, and she’s still pissed off about everything. The Enquirer didn’t claim that Hall and Carpenter were at each other’s throats or anything, just that they have been giving each other the silent treatment and everything is really awkward.

Now we have a new reason for the awkwardness – Radar claims that for the past five months, Hall has been quietly dating a 25 year old Dexter staffer. Hall is 40 – so, it’s kind of mid-life-crisis-y. Especially considering that most of these quotes seem to come from the 25-year-old’s friends, and they all sound like teenagers.

Dexter star Michael C. Hall has a secret new girlfriend and RadarOnline.com has exclusively learned she is 15 years his junior. The 40-year-old actor has been having secret trysts with Vanessa Abrue, a Showtime staffer, and the two have been going to great lengths to keep the relationship low-key since they started dating in March – just three months after his ex, Jennifer Carpenter, filed for divorce from him.

“No one would ever suspect these two were together because she isn’t what anyone would expect Michael to be with,” the insider said. “They hardly go out together but when they do it’s always with a group of people so no one would suspect he’s with someone.”

According to the source, Vanessa brags about dating Michael to her friends but uses the code names “Ginger” or “my friend” when she speaks about him in front of other people.

The young brunette bears a striking resemblance to Hall’s 31-year-old ex-wife and Dexter co-star, Carpenter, who he was married to for nearly two years.

“Vanessa would constantly talk about Michael texting her at all hours of the night but said she thought it was all worth it,” the source told RadarOnline.com. “They mostly hang out at Michael’s house, but when she does go out in public with him it’s only with others and she walks at a distance.”

Vanessa, 25, has also worked on the television show Weeds but has been a staffer on Dexter since last season, and spends so much time with Michael that people think she is his assistant.

“It’s more like Michael, Vanessa and a few others that work on Dexter that are not actors. They are all close to Vanessa’s age,” the insider said.

“When they all hang out at Michael’s, Vanessa would always stay the night with him but I don’t think Michael realizes how much Vanessa talks about him to friends.”

Another source tells RadarOnline.com that they think Michael dating Vanessa is “gross” because he is so much older than she is but believes that he is “going through a midlife crisis dating a twenty-something.”

The insider says that no one says anything because Michael, who battled cancer last year, is fun to hang around with and gets them into showbusiness events.

As for rumors that Michael was dating blonde beauty Julia Stiles, who also starred on Dexter last season, the insider said that was just a ruse and they were never together.

“The Julia Stiles speculation last season was an ‘inside’ lie created to use Julia as a scapegoat and throw people off,” the source said.

“Vanessa even mentioned Julia as a scapegoat at one point.”

Michael has been married twice – first to Amy Spanger, which ended in 2006 after three years and then he eloped with Carpenter in 2008 but they filed for divorce in December 2010.

[From Radar]

Ugh. So, Michael is hooking up with some 25-year-old chick (you can see photos of the girl here) on the set of his show, but he wants to keep it all on the downlow, so they pull the whole “we’re going out as a group” thing – the kind of scheme usually used to fool your parents when you’re 14. Sounds more like Michael just doesn’t want anyone to know he’s boning this chick on the side, and he feeds her these bizarre lines (“Julia Stiles is the scapegoat”) and this chick buys it. I guess I just don’t understand why this whole thing is so controversial? It’s not like a 15-year age difference is that shocking at this point. And sure, it does sound like Michael is having a mid-life crisis. I suspect he’s douchey about women. Also: what’s it going to take for Michael to date someone outside of work? He’s already working with one pissed off woman who he used to sleep with.

Photos courtesy of WENN.