Perhaps it was too much sunshine, too many glasses of Pimms or the over-excitement of Andy Murray currently storming Wimbledon...
But some of the famous faces spotted in the crowd at the tennis championships this week have looked a little, er, tired.
From Game of Thrones actress Gwendoline Christie to Downton Abbey's Lily James - see more sleepy-looking stars watching the games on Centre Court below:
Downton actress Lily James lets out a few, lengthy yawns as she watches Rafael Nadal beat Martin Klizan in a four-set victory earlier this week.
Gwendoline Christie looks like she could be stifling a yawn as she watches Nadal work his magic on Centre Court. Or maybe this is her excited face?
A pregnant Kimberley Walsh plays with her hair and checks her phone while actress Kara Tointon takes pictures during the match on Tuesday afternoon.
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Andy Murray's coach Amelie Mauresmo looks like she might have somewhere better to be as she watches Murray beat Blaz Rola yesterday afternoon.
Sir David Jason's looking a bit pooped as he watches Andy Murray whop Belgian David Goffin 6-1, 6-4, 7-5 on Centre Court on Monday.
The actor looks like he's taking drastic measures to stay awake and using his hand to keep his eyes open.
Let it all out, Jason!
It's catching, as John Bishop's wife Melanie lets rip with a mighty yawn as she and the comedian watch Murray beat Goffin.
Alesha Dixon has to lean her sleepy head and weary shoulders on partner Azuka Ononye as they watch Nadal beat Klizan.
Naomi Gordon is news writer mainly covering entertainment news with a focus on celebrity interviews and television.
