SHE lied.

“The Sopranos” star

Drea de Matteo – who plays (oops, played) the conflicted girlfriend Adrianna on the mob opera – swore she could do both shows after agreeing to star next season in NBC’s “Friends” spinoff, “Joey.”

Officially, HBO backed her up, saying she had been signed to a sixth season of “The Sopranos.” But yesterday, everybody admitted they had fudged the truth to protect last Sunday night’s shocking plot twist – Adrianna’s whacking.

“We weren’t going to come out and say that Drea may or may not make it through this season so she would have no problems with [going to] ‘Joey,’ ” an HBO spokesman said yesterday.

De Matteo – who did not return phone calls yesterday – was just as duplicitous last March on ABC’s “Jimmy Kimmel Live” when news broke that she had landed one of the most sought-after jobs in Hollywood – playing Matt LeBlanc’s sister on the “Friends” spin-off.

“It seems like you’re going to get killed this year,” Kimmel said – echoing what just about every other fan of the show suspected when she got the “Joey” role.

“Oh, really,” she said, laughing. “We have one more season left. I have to make it through this season. If this was the last season, I probably would not make it.

“I will survive,” de Matteo said. “I will survive.” So do HBO officials feel, well, a little guilty about not telling the truth?

“At the time, it was true that Drea was contracted for a sixth season. That means the character has to survive,” said the HBO spokesman.

It’s possible, he said, she could return in another dream sequence, as other dead characters have before.