Judge John Deed star Martin Shaw had to pull out of a stage performance on Wednesday after he was taken ill during the first act.
The curtain came down during the matinee showing of A Country Girl at Shrewsbury's Theatre Severn after the 65-year-old began to feel unwell.
Shaw's agent told the BBC the actor had been suffering from cracked ribs and was taking antibiotics for a severe chest infection.
An understudy went on in Shaw's place.
Shaw only took to the stage out of "dogged determination," agent Roger Charteris said.
"He didn't want to let his fans down."
Jackson Cummings, marketing manager for the Theatre Severn, said: "As a precautionary measure paramedics were called. Martin walked out to them and was taken to hospital."
The play, which is based on the 1954 Oscar-winning film starring Bing Crosby and Grace Kelly, is currently touring the UK before transferring to the West End in October.
It is due to end its run at the Theatre Severn on 21 August and move on to the Milton Keynes Theatre on 26 August, but it is unclear when Shaw will return to the stage.
"Martin will want to be on stage tonight, but whether that's possible is up for the doctor's decision," Mr Charteris said.
Shaw, who rose to fame in TV series The Professionals currently plays the title role in crime drama Inspector George Gently.
His stage roles include A Streetcar Named Desire, Look Back In Anger and An Ideal Husband, for which he received a Tony Award nomination in 1996.