Emily Deschanel and David Boreanaz in the heart-wrenching 100th episode of Bones, airing April 7 on Global and April 8 on Fox.

Big changes are coming on Bones. Fans can feel it in their ... well, you know.

It starts with the 100th episode, which airs next week (Wednesday, April 7 on Global; Thursday, April 8 on Fox). And star David Boreanaz hinted this week there are major developments in the upcoming season-finale, too.

“After the 100th, we’ll see (Booth) has to make some changes internally,” said Boreanaz, speaking of his character, FBI special agent Seeley Booth.

“Both these characters grow, in a way, from the past, where they came from, with some insight into the future to see what’s going to happen next.”

Bones also stars Emily Deschanel as Dr. Temperance Brennan, a forensic anthropologist nicknamed Bones. The slow-building but now ratings-rich series has lived off the classic will-they-or-won’t-they romantic tension between Booth and Brennan, and that situation hits a crossroads next week.

We have to say, without ruining it for anyone, the final scene in the 100th episode is very strong, and exquisitely acted by both Boreanaz and Deschanel. To say that its “heartbreaking” is too strong, but certainly the term “heart-wrenching” would apply.

The 100th episode, directed by Boreanaz and titled The Parts in the Sum of the Whole, takes viewers back six years as Booth and Brennan recount the first case they worked on together. With Dr. Lance Sweets (John Francis Daley) finishing his book on their partnership, Booth and Brennan take the opportunity to set the record straight, but the process stirs up unfinished business.

Boreanaz has been a familiar face on TV for a long time, not only with Bones but with his previous roles on Buffy the Vampire Slayer and Angel. He was asked if he ever has taken a minute to be Sally Field, staring into the mirror and exclaiming, “They like me, they really like me.”

“That’s pretty hard to do,” said Boreanaz, a hardcore Philadelphia Flyers fan who is just too much of a competitor to relax.

“It’s in my competitive nature to set the bar high. I’m proud of the work I’ve done and that I’ve been so successful in this arena. But to be able to sit back and smell the roses? I can do that, but it’s difficult.”

Boreanaz, 40, said he still gets recognized as the guy from Buffy and Angel, but with 100 episodes of Bones under his belt, fan reaction increasingly leans toward that show.

“We were at an event (last weekend), and everyone was screaming ‘Bones’ at me — well, I don’t play Bones, I play Booth!” Boreanaz said with a laugh.

“Buffy was so long ago, as was Angel. But it’s a blessing to be part of great shows that are recognizable.

“Fans have supported me for a long time. And I’ve got a lot more up my sleeve, so I look forward to giving them even possibly another show down the line, or more characters to love.”

That said, Boreanaz feels that Bones — which the network and studio initially wanted to be a much darker procedural, rather than the character-focused dramedy it has become — is running on full power now.

“I think there are plenty more episodes,” Boreanaz said. “I started this venture with a pilot and didn’t really think about where it was going to go, just taking it episode to episode. I don’t set myself up too much for discouragement if it were to end tomorrow. But I think it really has found its legs.

“I think we’re at a good place, but it can get bigger and better. It’s going to be fun to shake things up a bit at end of this season.

“We’re the little show that could, and the little show that has.”

bill.harris@sunmedia.ca