Hearts manager Craig Levein says bringing Norwich City's Steven Naismith to Tynecastle on loan represents a "coup" for the club.
The 31-year-old, who has 18 months to run on his contract at Carrow Road, has signed until the end of the season.
"I think he'll be a huge player in the dressing room and a great example to the rest of the team," said Levein.
"Hearts showed the most enthusiasm to get something done as quickly as possible - I like that," said Naismith.
Naismith, capped 45 times for Scotland, made three Norwich appearances in August before suffering an ankle injury.
He is the second player to move to the club in this transfer window following Manchester United defender Demetri Mitchell, who also joined on loan until the end of the season.
'Raring to go'
Expressing delight at sealing his loan move to the Scottish Premiership, Naismith added: "It is a club which obviously has had its difficulties in the past but it is definitely flourishing now under the leadership of [owner] Ann Budge and the gaffer, and if I can help that move forward I would be delighted to do so.
"I took a bit of time to think of all my options and it is more about the whole package instead of moving for the sake of moving and Hearts definitely ticked all the boxes.
"I know what the gaffer is about. That played its part. I've spent the morning looking around the training base and the stadium and it's incredible what changes have been made, especially at Tynecastle."
Naismith is added to the squad for this weekend's Edinburgh derby in the Scottish Cup and the player described facing Hibernian at Tynecastle as "a good game to start with".
"I am raring to go, to be involved in matches again but that adds a little bit more to it, that it is a derby at home and I will be eager to get going."
Levein added: "It's a bit of a coup to bring somebody in of Steven's quality."
Describing Naismith as "a fantastically talented football player," the Hearts boss added: "He'll bring a bit of nous, experience, energy and enthusiasm - which he has in abundance. He's also got goal-scoring ability."
Analysis - 'He will be a great signing'
"It is a marquee signing for Hearts," former Scotland assistant coach Peter Houston told BBC Sportsound. "They have had six successive clean sheets so Craig [Levein] has sorted the defence out. But he has always said they need a bit more quality in the final third, and Stevie Naismith adds that. He can link up, drop off the main striker, play as the main striker, come in off the sides.
"He is a humble guy too, and the young players at Hearts will learn from his experience. He was different class when I was with Scotland. He was a big Rangers player at the time, when they were champions, but his attitude, work-rate and effort, his mixing with younger players in the squad, it was so visible. Hearts have shown they want him, and he will be a great signing."
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