Mark Ronson was turned down for a collaboration by Kendrick Lamar, although the producer insists he doesn't take the snub "personally".
The 'Uptown Funk' hitmaker has teamed up with some of the world's biggest stars on tracks in the past - including Miley Cyrus, Bruno Mars, Adele, Lady Gaga, Lily Allen, and the late Amy Winehouse - but has admitted that not everyone agrees to appear on his chart-topping songs, as rapper Kendrick Lamar once turned down Mark's request to collaborate.
When asked if people ever turn him down, Mark said: "A lot of people. But I never really take it personally because I know how bad I am at texting people back ... I don't really want to call anybody out ... Kendrick Lamar ... they are just people I am such a fan of. I love finding the next new people as well."
And the 43-year-old producer goes to extreme lengths to win over the people he wants to make music with, as he even crafted a handwritten letter to send to 'Hotline Bling' hitmaker Drake.
He added: "He seemed like he'd be the kind of person into a handwritten letter, he might appreciate the thought. So I did I found this black nice paper and wrote in this gold pen, he probably thought I was going to ask him out, I just wanted him on a track."
Despite being a chart-topping DJ and producer, Mark says he often finds himself getting "annoyed" by his own music, because he gets "pretty sick" of hearing his tracks being played everywhere he goes.
Speaking during an appearance on 'The Jonathan Ross Show', which airs on Saturday, the 'Nothing Breaks Like A Heart' musician said: "It's very annoying, 'Uptown Funk.' You work so hard when you're working on a song, that song took us seven months to make and then by the time before it even comes out you're pretty sick of it. But with a song like 'Uptown Funk' it has brought so much joy. That's what is fun, seeing other people get into the music."