He describes how he got selected in this Guardian article from 2010.
https://www.theguardian.com/politics/2010/mar/18/chris-bryant-gay-mp-civil-partnership
It's fascinating that the Rhondda chose Bryant – gay, a former Anglican priest, and someone who had dallied with the Conservatives as a student – in the first place. Had he been surprised to be picked to fight the 2001 election? "I fell off the chair," he says, "and my opponents [for the nomination] certainly did. I had promised my then partner that I wouldn't get selected, but I did. He was very worried that I'd disappear into politics and he'd never see me again, and becoming an MP didn't do much for that relationship."
Fifty-two people applied for the candidature and a local councillor was hot favourite to win, but Bryant says hard work and knocking on the doors of every one of the constituency's 700 Labour members produced the unlikeliest of upsets. "Eight of us were put on the shortlist and there was a hustings. I did my 'I am what I am' moment, and got a standing ovation. I thought it was better to get selected on an honest basis."
Seems quite an odd tale. He promised his partner that he wouldn't get selected, then put in the hard work of knocking on the doors of all the local Labour members to make sure he did.