Poison singer Bret Michaels, who is recovering from a brain haemorrhage, has been re-admitted to hospital after suffering a "warning stroke".
Doctors said the star suffered a minor stroke. Tests later found a hole in his heart.
The condition is operable, but Michaels will receive blood thinners and outpatient treatment.
A statement on Michaels' website added it was "highly unlikely" the problems were related to his recent illness.
The singer, 47, is one of the finalists in the US version of The Celebrity Apprentice and had hoped to take part in the live finale on 23 May.
Most of the NBC show was shot before Michaels' string of medical emergencies.
Michaels, who suffers from diabetes, underwent an emergency appendectomy two weeks before suffering a brain haemorrhage on 25 April.
He was discharged earlier this month and was interviewed by Oprah Winfrey about his experience.
However, he was rushed back to hospital this week after suffering numbness on the left side of his body, predominantly in his face and hands.
His manager, Janna Elias, said Michaels was "walking, talking, continuing his daily rehab and very happy to be alive."
A statement on the singer's website quoted neurosurgeon Dr Joseph Zabramsk, who said: "Without a doubt he is very determined to get healthy and make a 100% recovery".
However, he added, "Bret's brain and body are not quite 100% yet".
Hair metal band Poison scored eight hits in the UK between 1988 and 1993, including Unskinny Bop and Every Rose Has Its Thorn.