The Lawson frontman previously confirmed that the single 'When She Was Mine' was about his relationship with King and she described the song as her "favourite track of the moment".
"When we split up, it inspired me to write songs, such as 'When She Was Mine'," Brown told Metro.
He added: "We're still friends and she likes the band. She sent me a message saying she's liked the singles. She's an amazing girl and we're still friends."
Asked if it was strange to be the subject of an album, Brown said: "Yeah, it must be. I don't know how she feels about it - whether it's flattering or what.
"She hasn't heard a lot of the songs. There's nothing saying, 'I hate you' or anything. It's reminiscing about the good times.
"It's just real-life stuff everyone can relate to, whether it's Mollie from The Saturdays or someone round the corner."
When King and Brown were dating, the Saturdays star claimed to have kissed only three men in her life.
She later had a relationship with model David Gandy but the pair split in February this year.