The RNLI says the man and boy were were swept out to sea off Aberffraw, on the west coast of Anglesey.
The man was able to make his way back to shore, but the child is still missing.
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The star celebrates beating Justin Bieber into second place as her song becomes a hit again after a performance at the total solar eclipse.
Later in the night cloud will thicken bringing hill fog, mist and some patchy drizzle by the early hours.
The Welsh singer sang her infamous track during yesterday's solar eclipse.