The group were yesterday split into two teams and placed in separate rooms containing a shredder loaded with the opposite half's letters.
Big Brother announced that the first group to press a button and shred the papers would receive their own messages from home. However, if neither team stepped up, everyone would lose out.
While the team of Denise Welch, Frankie Cocozza, Gareth Thomas and the Shannon twins locked in the task room appeared reluctant to betray their housemates, the group of McLean, Kirk Norcross, Michael Madsen, Natalie Cassidy and Romeo Dunn in the living room were more open to the possibility.
As Madsen began to crawl across the floor towards the button, stopping just short, married mother-of-two McLean volunteered to do the deed.
"I'd shred theirs for mine. I'm sorry, I'm being honest," she announced. "The girls have not got children and neither does Frankie. People with children need a letter so we can know that our kids are alright. I want my letter."
When Norcross said he couldn't bring himself to activate the shredder, McLean replied: "But I could. I'm happy to press it now. I'm doing it. I want my letter."
Despite losing out on their own letters, the other group appeared to accept the glamour model's decision.
Thomas said that he was happy to have the parents in the other team - Madsen, McLean, Cassidy and Dunn - receive their letters, while Welch said she could cope without hearing from her two children for a few more days, as she knew they were safe.
McLean, meanwhile, was comforted by her teammates as she broke down in tears on the sofa.
The five received their messages later in the night.
Watch Nicola McLean receive her letter from home below: