'T.J. Hooker' Star James Darren Dead at 88

James Darren, famous for his work on movies like "Gidget" and TV shows like "T.J. Hooker" and "Star Trek: Deep Space Nine," is dead.

The veteran actor died peacefully in his sleep Monday at Cedars-Sinai Hospital in Los Angeles ... his son, Jim Moret, confirmed to TMZ.

The cause of death is unclear, but James' son says his famous father was having heart issues and was being treated at the hospital's cardiac unit. We're told James initially went to the hospital for an aortic valve replacement, but was deemed too weak to undergo the procedure and was sent home ... only to be taken back to the hospital.

James became a teen idol back in the day when he played a surfer known as Moondoggie on 1959's "Gidget" and its two sequels ... "Gidget Goes Hawaiian" and "Gidget Goes to Rome."

On TV, James had a recurring role on "T.J. Hooker" as police officer Jim Corrigan ... appearing in 66 episodes across four seasons.

James also had a recurring gig on 'Deep Space Nine' ... playing holographic lounge singer Vic Fontaine in the late 1990s TV series.

In addition to acting, James enjoyed a successful career as a singer ... and he also directed a variety of TV episodes on shows like "Melrose Place," "Beverly Hills, 90210" and "The A-Team" ... among others.

James sang the theme song for "Gidget" and performed another track in the flick ... and in 1961 he reached No. 3 on the Billboard charts with "Goodbye Cruel World."

He's survived by his 3 sons and 5 grandkids.

James was 88.