The One Direction star - who achieved meteorological fame as part of the boy band - has been offering support to the 'In My Blood' hitmaker and has told the singer he is just a phone call away if there's anything he needs.
Speaking to MTV's TRL, Liam said: ''With the way this lifestyle is, we don't help each other and there's just not much point to it. I went and saw Shawn Mendes recently when I was at an awards show. I think he's doing fantastic, but I could hear the slightest bit of sorrow in a recent song he wrote, and I wanted to make sure he was all good.
''He's only 19 years old - not to belittle him in any way, shape, or form because I think he's incredible. He's got his head screwed on and he's gone about it the right way. Now [that] he's known all over the world, it's a bit of a transformation. I just wanted to offer, 'If you ever have a problem or something's going on, call me and we can have a chat about it.'''
Liam has been open about his fame struggles in the past, admitting recently that he was nearly ''killed'' by his success.
Asked to recall his hardest emotional battle, Liam confessed: ''I've had a few, there have been some tough times. When the band started our break I struggled with the idea of becoming famous again, it scared the living daylights out of me. Because the last time it nearly killed me, frankly. So I had to figure out a way to make it work for me - rather than me work for it.''
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