Sylvester Stallone and Bruce Willis used to be attached at the hip, but the “Tulsa King” actor said he hadn’t spoken to his “Expendables” co-star much since Willis’ aphasia diagnosis.

“Bruce is going through some really, really difficult times,” Stallone said in an interview with the Hollywood Reporter published Monday.

“So he’s been sort of incommunicado.” The “Rocky” actor added that not speaking to Willis “kills me” and “it’s so sad.”

Stallone’s comments come months after Willis’ daughter, Rumer Willis, announced in March that the “Die Hard” actor was diagnosed with the cognitive disorder and would step away from his acting career.

According to the National Aphasia Assn., aphasia is an acquired communication disorder that impairs the ability to process language but does not affect intelligence.

When news of Willis’ aphasia diagnosis broke, Stallone showed support on his Instagram page, posting pictures of their friendship over the years.

“We go back a long way, praying for the best for you and your wonderful family,” Stallone captioned his March post.

Not long after the shocking announcement, The Times reported that Willis exhibited signs of decline in recent years.

Filmmakers who worked with him said he had difficulty remembering his lines and could not perform action scenes.

The condition might have halted Willis’ career, but the actor is still expressing his talent in other ways.

In August, Willis’ wife, Emma Heming Willis, shared a video of the actor playing the blues on his harmonica with musician Derek Richard Thomas.