Dating

10:00 AM PT -- A source close to Elon tells TMZ, "Amber invited Elon to her favorite restaurant for lunch, which serves cuisine from her home town of Austin. They caught up and kissed goodbye, but are not back together."

Amber Heard and Elon Musk wasted no time re-igniting an old flame ... marking their territory with a kiss.

The actress and the genius behind Tesla and SpaceX grabbed lunch Thursday in L.A. and, just before hopping in separate cars, Elon reached behind Amber and planted a smacker.

The PDA-heavy lunch comes about a month after TMZ broke the story ... Amber and Elon were together for the first time since announcing their breakup in August.

Shawn Mendes and Hailey Baldwin didn't need mistletoe Thursday as they strolled to the Toronto Christmas Market.

The freshly-minted couple are in Mendes' hometown for the holidays. The day before they hit up Daniel Caesar's concert.

Hailey's been linked to Bieber, Drake, Cameron Dallas ... but, times and seasons change ... and now it's all about Shawn.

Hailey's been mum about Justin's blowup with Selena ... as we reported Selena was furious Justin contacted Hailey to make amends over their breakup, and it landed them in couples therapy.

Baldwin's clearly a bit distracted.

Sofia Richie got down and dirty -- sexy dancing for boyfriend Scott Disick -- and it was all while her dad's music blasted in the background.

Disick shared the clip of a 19-year-old Richie in some skimpy Santa gear moving her hips and shaking her ass in his kitchen. It's a whole lotta awkward, considering the song she's gyrating to is Lionel's "All Night Long."

34-year-old Scott has been seemingly settled down since getting with Richie months ago ... looks like their recipe for fun is some one-on-one dance parties.

Unicorns and rainbows go hand-in-hand with bliss, and it looks like Sam Smith has found his with "13 Reasons Why" star Brandon Flynn.

Smith essentially confirmed he and Flynn are an item by posting a pic of the two of them together in a London elevator wearing matching unicorn headgear.

Rumors the two were dating began to swirl back in October when Smith and Flynn were spotted making out on the streets of New York City, but they never confirmed they were a couple.

Here's a new sign Anna Faris and her bf are getting really serious -- they're blending their families for public outings.

Anna, her son Jack, bf Michael Barrett and his son hit up the Redondo Beach Pier Friday where they chowed down on some fish and chips.

This comes on the heels of Micheal helping Anna look for a new crib in the Venice, CA area. They were also spotted hanging out with Jack earlier this week.

David Foster and girlfriend Katharine McPhee seem to know that the couple that plays together one-horse open sleighs together ... hey, it's that time of the year.

Dave and Kat were just two of many celebs that attended singer-songwriter Carole Bayer Sager and her hubby Bob Daly's holiday party Saturday night ... but it appears they were also among the few that actually performed onstage.

Kim Kardashian caught the magic on camera, showing D&K doing a rendition of "White Christmas" with the help of Babyface -- and then pairing off to do Kelly Clarkson's "My Grown Up Christmas List." Dave handled piano -- and, naturally, Kat was on vocals.

Other musicians like Keith Urban and Joe Walsh sang Xmas ditties as well, and were even joined by the likes of Hugh Jackman at one point.

Tiffany Haddish is done dating scrubs ... aka a busta ... aka a broke ass. Wanna get some love from her? Better rate 700 and above!

We got the "Girls Trip" star at LAX Wednesday night and talked to her about dating again. She'd gone on "The Breakfast Club" and said she wants someone better than her ... and that includes their credit score.

Sprained MCL be damned ... Blake Griffin fought through his knee pain Tuesday night to hang out with Kendall Jenner -- and he didn't even need crutches!

The L.A. Clippers superstar gimped over to the Improv comedy club -- where he met up with his rumored girlfriend. Blake tried to go incognito, but it's hard when you're a 6'10" black redhead.

Griffin suffered a sprained MCL during a collision with Austin Rivers last week -- and he's expected to miss around 2 months.

Good news ... he was moving around pretty good at the comedy club -- but jumping, sprinting and cutting is a whole other ball game.

Anna Faris is not just moving on ... she's moving.

Check out these pics of Anna looking at houses in Venice, CA with serious boyfriend Michael Barrett. They checked out 2 homes ... super modern cribs, though not directly on the ocean.

TMZ broke the story ... Chris Pratt filed for divorce Friday and Anna filed her response at the exact same time. It's unclear who's living in the family home, but we're guessing it will be sold as part of the property settlement.

Unclear if Michael's moving in with Anna or whether he's just tagging along.

Chris Pratt, who just filed for divorce, will not join the hordes on online dating services.

We got Chris leaving Jimmy Kimmel's studio in L.A. Monday night, and asked for a status update on his Facebook impostor sitch. Sounds like it's still pending.

Chris sent a message to his female fans over the weekend warning 'em of a guy posing as him on the social media site ... supposedly asking for numbers and dates.

David Foster was sketchy about his relationship with Katharine McPhee, but not anymore ... he wants you to know they're totally a couple!

David and Katharine were smooching it up during lunch Thursday in Bev Hills at E Baldi. They've been seen together a lot, and they were clearly together but never said so ... and now there's no need.

Gotta say ... David's got game. Linda Thompson, Yolanda Foster, etc. etc. He even dated Oksana Grigorieva.

Sarah Hyland and new BF Wells Adams hit up Urban Outfitters Friday and found what they were looking for.

The freshly minted couple was perusing the aisles for clothes and housewares. The "Modern Family" star and the "Bachelor" contestant have been seen out a lot recently.

They went to the Lakers game Tuesday night and were way more into each other than the game ... or so it seemed.

Paris Jackson's down under in Melbourne for the Australian Cup horse race, and she showed up for the event with a mystery guy ... plenty of women would pick to win, place AND show.

Paris and the guy seemed pretty tight during the event -- which is kinda like the Kentucky Derby of Oz. Despite what looked like canoodling and hand-holding ... we're told the guy's just a friend, and they were with a group.

Check out the pics though ... doesn't look like Paris was too into the races, and we can't blame her. The dude's got the hair, the face and the sharp suit.

A former Grindr employee is suing the gay dating service, claiming the Human Resources Supervisor slipped him a drug at the company's 2016 Xmas party and anally raped him.

The plaintiff, who is listed as John Doe, claims Daniel Cabanero is the one who drugged him and then allegedly put him in a car, and took him to a hotel room where he anally penetrated him.

John Doe says he woke up and Cabanero was holding him down on the bed in the middle of the sexual act.

J.D. says he lost consciousness again and when he regained it he immediately went to the E.R. where he was "subjected to a highly invasive and humiliating rape examination."

He says he went to law enforcement, which conducted an investigation and he believes the investigation is ongoing.

J.D. goes on to claim various Grindr officers were aware he was impaired at the party but did nothing to protect his health and safety.

J.D. claims the company encouraged sexually explicit language, sexual inuendo and sexual misconduct.

Justin Bieber and Selena Gomez have put the dating rumors to bed ... because they're clearly dating!

The Biebs and Selena hung out AGAIN on Wednesday morning in L.A. Sure looks like Selena has all the feels.

They also went on a bike ride and looked super cozy.

The exes reconnected over the last few weeks and have spent lots of time together ... grabbing grub, praying in church and then there are those late-night visits.

The deck is clear for Selena ... she and The Weeknd broke up several weeks ago, and it looks like Justin didn't waste any time swooping in.

Justin Bieber and Selena Gomez had quite a weekend away from The Weeknd ... they grabbed breakfast together Sunday morning -- just the 2 of 'em.

JB and Selena were chatting it up at a cafe in Westlake Village ... with Bieber rockin' a hoodie, and Selena not wearing much to cover up.

This is the 3rd sighting recently where the 2 exes have hung out ... again, with Abel nowhere in sight. Justin was just at Selena's house last Sunday ... and stayed 'til midnight.

Like we told you ... Selena's BF was fully aware of them hanging out, and we're told he's totally cool.