Boy George was left in tears as he delved into his family's Dublin history on BBC One's Who Do You Think You Are? on Wednesday night, describing it as "sadder than even I could have imagined".

Warning: spoiler alert!

In one of the most memorable episodes of the long-running series, the Culture Club singer discovered more about his grandmother Bridget Kinahan's years spent in St Vincent's Industrial School, Goldenbridge, and the facts behind the execution of his great-uncle, IRA volunteer Thomas Bryan, in Mountjoy Prison during the War of Independence in 1921.

An official document said George's grandmother Bridget Kinahan had been found "wandering on the streets", but he learned she actually had been outside her family's home at the time. She was sent to Goldenbridge aged six in 1919 and spent ten years there.

Paying tribute, George described his grandmother as "a survivor" and "a formidable force".

There were further shocks when George explored documents related to his great-uncle, Thomas Bryan.

Having visited the Tenement House & Museum at 14 Henrietta Street in Dublin, George was later told that Thomas Bryan had actually lived at that address when he married George's great-aunt, Annie Glynn.

His journey then took him to Kilmainham Gaol, where he found out about the circumstances surrounding Thomas Bryan being sentenced to death for taking part in an IRA ambush in 1921. His wife Annie was pregnant at the time.

Thomas Bryan was subsequently transferred to Mountjoy Prison in March 1921, with George visiting the room where his great-uncle was executed.

Thomas Bryan, George had learned, was one of the IRA volunteers collectively known as the 'Forgotten Ten'. The group, which included Kevin Barry, were originally buried in unmarked graves in the grounds of Mountjoy. Their remains were exhumed in 2001 and reinterred in Glasnevin Cemetery with full State honours.

While in Glasnevin Cemetery, George then received documents showing how Thomas Bryan and Annie Glynn's one-day-old baby died four days before his execution. Annie Glynn later passed away in 1930 from tuberculosis.

After visiting Thomas Bryan's resting place, George visited the grave of his great-aunt. 

"Having now found out what she endured, it's just unimaginable to think that while her husband was waiting to be hung, she lost their first child," said George. "And we'll never know whether he knew - whether he went to his death knowing his firstborn had already died. I really hope he didn't know."

"My family's association to really important parts of Irish history is a revelation," George then reflected. 

His final destination was Kavanagh's pub beside Glasnevin Cemetery, where George joined the band Lankum in a performance of the song he remembered singing as a child, Kevin Barry. 

"I think for me music is such a powerful medium," concluded George. "And Kevin Barry as a song still resonates, because I knew it had a real importance, but I didn't really know how it related to me.

"To be able to walk in those footsteps and find out family history has been very, very enlightening and powerful for me." 

The response to the episode was overwhelmingly positive: